Migrate remaining java skylark types to skylarkbuildapi

RELNOTES: None.
PiperOrigin-RevId: 198911668

16 files changed, 946 insertions, 595 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/bazel/rules/JavaRules.java b/src/main/java/com/google/devtools/build/lib/bazel/rules/JavaRules.java
index 7da470d40a..e670f9f1c4 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/rules/JavaRules.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/rules/JavaRules.java
@@ -88,7 +88,7 @@ public class JavaRules implements RuleSet {
     builder.addSkylarkAccessibleTopLevels("java_common",
         new JavaSkylarkCommon(BazelJavaSemantics.INSTANCE));
     builder.addSkylarkAccessibleTopLevels("JavaInfo", JavaInfo.PROVIDER);
-    builder.addSkylarkAccessibleTopLevels("java_proto_common", JavaProtoSkylarkCommon.class);
+    builder.addSkylarkAccessibleTopLevels("java_proto_common", new JavaProtoSkylarkCommon());
 
     try {
       builder.addWorkspaceFilePrefix(
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/JavaConfiguration.java b/src/main/java/com/google/devtools/build/lib/rules/java/JavaConfiguration.java
index 294e4054f5..4f2991cba6 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/java/JavaConfiguration.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/JavaConfiguration.java
@@ -28,9 +28,7 @@ import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
 import com.google.devtools.build.lib.events.Event;
 import com.google.devtools.build.lib.events.EventHandler;
 import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec;
-import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
-import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
-import com.google.devtools.build.lib.skylarkinterface.SkylarkModuleCategory;
+import com.google.devtools.build.lib.skylarkbuildapi.java.JavaConfigurationApi;
 import com.google.devtools.common.options.TriState;
 import java.util.List;
 import java.util.Map;
@@ -39,12 +37,7 @@ import javax.annotation.Nullable;
 /** A java compiler configuration containing the flags required for compilation. */
 @AutoCodec
 @Immutable
-@SkylarkModule(
-  name = "java",
-  doc = "A java compiler configuration.",
-  category = SkylarkModuleCategory.CONFIGURATION_FRAGMENT
-)
-public final class JavaConfiguration extends Fragment {
+public final class JavaConfiguration extends Fragment implements JavaConfigurationApi {
   /** Values for the --java_classpath option */
   public enum JavaClasspathMode {
     /** Use full transitive classpaths, the default behavior. */
@@ -303,19 +296,14 @@ public final class JavaConfiguration extends Fragment {
     this.useLegacyBazelJavaTest = useLegacyBazelJavaTest;
   }
 
-  @SkylarkCallable(name = "default_javac_flags", structField = true,
-      doc = "The default flags for the Java compiler.")
+  @Override
   // TODO(bazel-team): this is the command-line passed options, we should remove from skylark
   // probably.
   public ImmutableList<String> getDefaultJavacFlags() {
     return commandLineJavacFlags;
   }
 
-  @SkylarkCallable(
-      name = "strict_java_deps",
-      structField = true,
-      doc = "The value of the strict_java_deps flag."
-  )
+  @Override
   public String getStrictJavaDepsName() {
     return strictJavaDeps.name().toLowerCase();
   }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/JavaRuntimeClasspathProvider.java b/src/main/java/com/google/devtools/build/lib/rules/java/JavaRuntimeClasspathProvider.java
index 63fbeedc6d..be9e29226b 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/java/JavaRuntimeClasspathProvider.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/JavaRuntimeClasspathProvider.java
@@ -19,8 +19,7 @@ import com.google.devtools.build.lib.analysis.TransitiveInfoProvider;
 import com.google.devtools.build.lib.collect.nestedset.NestedSet;
 import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
 import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec;
-import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
-import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
+import com.google.devtools.build.lib.skylarkbuildapi.java.JavaRuntimeClasspathProviderApi;
 
 /**
  * Provider for the runtime classpath contributions of a Java binary.
@@ -28,9 +27,9 @@ import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
  * <p>Used to exclude already-available artifacts from related binaries (e.g. plugins).
  */
 @Immutable
-@SkylarkModule(name = "JavaRuntimeClasspathProvider", doc = "")
 @AutoCodec
-public final class JavaRuntimeClasspathProvider implements TransitiveInfoProvider {
+public final class JavaRuntimeClasspathProvider
+    implements TransitiveInfoProvider, JavaRuntimeClasspathProviderApi<Artifact> {
 
   private final NestedSet<Artifact> runtimeClasspath;
 
@@ -41,7 +40,7 @@ public final class JavaRuntimeClasspathProvider implements TransitiveInfoProvide
   /**
    * Returns the artifacts included on the runtime classpath of this binary.
    */
-  @SkylarkCallable(name = "runtime_classpath", documented = false, structField = true)
+  @Override
   public NestedSet<Artifact> getRuntimeClasspath() {
     return runtimeClasspath;
   }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/JavaRuntimeInfo.java b/src/main/java/com/google/devtools/build/lib/rules/java/JavaRuntimeInfo.java
index 0e8c1b6e89..d48db3d595 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/java/JavaRuntimeInfo.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/JavaRuntimeInfo.java
@@ -26,16 +26,14 @@ import com.google.devtools.build.lib.packages.NativeProvider;
 import com.google.devtools.build.lib.packages.RuleErrorConsumer;
 import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec;
 import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec.VisibleForSerialization;
-import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
-import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
+import com.google.devtools.build.lib.skylarkbuildapi.java.JavaRuntimeInfoApi;
 import com.google.devtools.build.lib.vfs.PathFragment;
 import javax.annotation.Nullable;
 
 /** Information about the Java runtime used by the <code>java_*</code> rules. */
-@SkylarkModule(name = "JavaRuntimeInfo", doc = "Information about the Java runtime being used.")
 @Immutable
 @AutoCodec
-public class JavaRuntimeInfo extends NativeInfo {
+public class JavaRuntimeInfo extends NativeInfo implements JavaRuntimeInfoApi {
   public static final String SKYLARK_NAME = "JavaRuntimeInfo";
 
   public static final NativeProvider<JavaRuntimeInfo> PROVIDER =
@@ -125,33 +123,18 @@ public class JavaRuntimeInfo extends NativeInfo {
   }
 
   /** The root directory of the Java installation. */
-  @SkylarkCallable(
-      name = "java_home",
-      doc = "Returns the execpath of the root of the Java installation.",
-      structField = true
-  )
+  @Override
   public PathFragment javaHome() {
     return javaHome;
   }
 
-  @SkylarkCallable(
-      name = "java_executable_exec_path",
-      doc = "Returns the execpath of the Java executable.",
-      structField = true
-  )
+  @Override
   /** The execpath of the Java binary. */
   public PathFragment javaBinaryExecPath() {
     return javaBinaryExecPath;
   }
 
-  @SkylarkCallable(
-      name = "java_executable_runfiles_path",
-      doc = "Returns the path of the Java executable in runfiles trees. This should only be used "
-          + "when one needs to access the JVM during the execution of a binary or a test built "
-          + "by Bazel. In particular, when one needs to invoke the JVM during an action, "
-          + "java_executable_exec_path should be used instead.",
-      structField = true
-  )
+  @Override
   /** The runfiles path of the Java binary. */
   public PathFragment javaBinaryRunfilesPath() {
     return javaBinaryRunfilesPath;
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/JavaSkylarkApiProvider.java b/src/main/java/com/google/devtools/build/lib/rules/java/JavaSkylarkApiProvider.java
index fe3e5d0fb0..b02fcd1295 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/java/JavaSkylarkApiProvider.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/JavaSkylarkApiProvider.java
@@ -24,26 +24,16 @@ import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
 import com.google.devtools.build.lib.collect.nestedset.Order;
 import com.google.devtools.build.lib.packages.SkylarkProviderIdentifier;
 import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec;
-import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
-import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
-import com.google.devtools.build.lib.skylarkinterface.SkylarkModuleCategory;
+import com.google.devtools.build.lib.skylarkbuildapi.java.JavaSkylarkApiProviderApi;
 import javax.annotation.Nullable;
 
 /**
  * A class that exposes the Java providers to Skylark. It is intended to provide a simple and stable
  * interface for Skylark users.
  */
-@SkylarkModule(
-  name = "JavaSkylarkApiProvider",
-  title = "java",
-  category = SkylarkModuleCategory.PROVIDER,
-  doc =
-      "Provides access to information about Java rules. Every Java-related target provides "
-          + "this struct, accessible as a <code>java</code> field on a "
-          + "<a href=\"Target.html\">target</a>."
-)
 @AutoCodec
-public final class JavaSkylarkApiProvider extends SkylarkApiProvider {
+public final class JavaSkylarkApiProvider extends SkylarkApiProvider
+    implements JavaSkylarkApiProviderApi<Artifact> {
   /** The name of the field in Skylark used to access this class. */
   public static final String NAME = "java";
   /** The name of the field in Skylark proto aspects used to access this class. */
@@ -78,11 +68,7 @@ public final class JavaSkylarkApiProvider extends SkylarkApiProvider {
     return JavaInfo.getProvider(provider, getInfo());
   }
 
-  @SkylarkCallable(
-    name = "source_jars",
-    doc = "Returns the Jars containing Java source files for the target.",
-    structField = true
-  )
+  @Override
   public NestedSet<Artifact> getSourceJars() {
     JavaSourceJarsProvider sourceJarsProvider = getProvider(JavaSourceJarsProvider.class);
     if (sourceJarsProvider == null) {
@@ -91,11 +77,7 @@ public final class JavaSkylarkApiProvider extends SkylarkApiProvider {
     return NestedSetBuilder.wrap(Order.STABLE_ORDER, sourceJarsProvider.getSourceJars());
   }
 
-  @SkylarkCallable(
-    name = "transitive_deps",
-    doc = "Returns the transitive set of Jars required to build the target.",
-    structField = true
-  )
+  @Override
   public NestedSet<Artifact> getTransitiveDeps() {
     JavaCompilationArgsProvider compilationArgsProvider =
         getProvider(JavaCompilationArgsProvider.class);
@@ -105,11 +87,7 @@ public final class JavaSkylarkApiProvider extends SkylarkApiProvider {
     return compilationArgsProvider.getTransitiveCompileTimeJars();
   }
 
-  @SkylarkCallable(
-    name = "transitive_runtime_deps",
-    doc = "Returns the transitive set of Jars required on the target's runtime classpath.",
-    structField = true
-  )
+  @Override
   public NestedSet<Artifact> getTransitiveRuntimeDeps() {
     JavaCompilationArgsProvider compilationArgsProvider =
         getProvider(JavaCompilationArgsProvider.class);
@@ -119,13 +97,7 @@ public final class JavaSkylarkApiProvider extends SkylarkApiProvider {
     return compilationArgsProvider.getRuntimeJars();
   }
 
-  @SkylarkCallable(
-    name = "transitive_source_jars",
-    doc =
-        "Returns the Jars containing Java source files for the target and all of its transitive "
-            + "dependencies.",
-    structField = true
-  )
+  @Override
   public NestedSet<Artifact> getTransitiveSourceJars() {
     JavaSourceJarsProvider sourceJarsProvider = getProvider(JavaSourceJarsProvider.class);
     if (sourceJarsProvider == null) {
@@ -134,20 +106,12 @@ public final class JavaSkylarkApiProvider extends SkylarkApiProvider {
     return sourceJarsProvider.getTransitiveSourceJars();
   }
 
-  @SkylarkCallable(
-    name = "outputs",
-    doc = "Returns information about outputs of this Java target.",
-    structField = true
-  )
+  @Override
   public JavaRuleOutputJarsProvider getOutputJars() {
     return getProvider(JavaRuleOutputJarsProvider.class);
   }
 
-  @SkylarkCallable(
-    name = "transitive_exports",
-    structField = true,
-    doc = "Returns transitive set of labels that are being exported from this rule."
-  )
+  @Override
   public NestedSet<Label> getTransitiveExports() {
     JavaExportsProvider exportsProvider = getProvider(JavaExportsProvider.class);
     if (exportsProvider != null) {
@@ -157,22 +121,12 @@ public final class JavaSkylarkApiProvider extends SkylarkApiProvider {
     }
   }
 
-  @SkylarkCallable(
-    name = "annotation_processing",
-    structField = true,
-    allowReturnNones = true,
-    doc = "Returns information about annotation processing for this Java target."
-  )
+  @Override
   public JavaGenJarsProvider getGenJarsProvider() {
     return getProvider(JavaGenJarsProvider.class);
   }
 
-  @SkylarkCallable(
-    name = "compilation_info",
-    structField = true,
-    allowReturnNones = true,
-    doc = "Returns compilation information for this Java target."
-  )
+  @Override
   public JavaCompilationInfoProvider getCompilationInfoProvider() {
     return getProvider(JavaCompilationInfoProvider.class);
   }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/JavaSkylarkCommon.java b/src/main/java/com/google/devtools/build/lib/rules/java/JavaSkylarkCommon.java
index 310e19733f..585770de10 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/java/JavaSkylarkCommon.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/JavaSkylarkCommon.java
@@ -27,10 +27,7 @@ import com.google.devtools.build.lib.collect.nestedset.NestedSet;
 import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
 import com.google.devtools.build.lib.events.Location;
 import com.google.devtools.build.lib.packages.Provider;
-import com.google.devtools.build.lib.skylarkinterface.Param;
-import com.google.devtools.build.lib.skylarkinterface.ParamType;
-import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
-import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
+import com.google.devtools.build.lib.skylarkbuildapi.java.JavaCommonApi;
 import com.google.devtools.build.lib.syntax.Environment;
 import com.google.devtools.build.lib.syntax.EvalException;
 import com.google.devtools.build.lib.syntax.Runtime;
@@ -40,123 +37,11 @@ import com.google.devtools.build.lib.syntax.Type;
 import javax.annotation.Nullable;
 
 /** A module that contains Skylark utilities for Java support. */
-@SkylarkModule(name = "java_common", doc = "Utilities for Java compilation support in Skylark.")
-public class JavaSkylarkCommon {
+public class JavaSkylarkCommon implements JavaCommonApi<Artifact, JavaInfo, SkylarkRuleContext,
+    ConfiguredTarget, SkylarkActionFactory> {
   private final JavaSemantics javaSemantics;
 
-  @SkylarkCallable(
-      name = "create_provider",
-      doc =
-          "Creates a JavaInfo from jars. compile_time/runtime_jars represent the outputs of the "
-              + "target providing a JavaInfo, while transitive_*_jars represent their dependencies."
-              + "<p>Note: compile_time_jars and runtime_jars are not automatically merged into the "
-              + "transitive jars (unless the given transitive_*_jars are empty) - if this is the "
-              + "desired behaviour the user should merge the jars before creating the provider."
-              + "<p>This function also creates actions to generate interface jars by default."
-              + "<p>When use_ijar is True, ijar will be run on the given compile_time_jars and the "
-              + "resulting interface jars will be stored as compile_jars, "
-              + "while the initial jars will be stored as full_compile_jars. "
-              + "<p>When use_ijar=False, the given compile_time_jars will be stored as both "
-              + "compile_jars and full_compile_jars. No actions are created. "
-              + "See JavaInfo#compile_jars and JavaInfo#full_compile_jars for more details."
-              + "<p>Currently only "
-              + "<a href='https://github.com/bazelbuild/bazel/tree/master/third_party/ijar'>"
-              + "ijar</a>"
-              + " is supported for generating interface jars. "
-              + "Header compilation is not yet supported.",
-      parameters = {
-        @Param(
-            name = "actions",
-            type = SkylarkActionFactory.class,
-            noneable = true,
-            defaultValue = "None",
-            doc =
-                "The ctx.actions object, used to register the actions for creating the "
-                    + "interface jars. Only set if use_ijar=True."),
-        @Param(
-            name = "compile_time_jars",
-            positional = false,
-            named = true,
-            allowedTypes = {
-              @ParamType(type = SkylarkList.class),
-              @ParamType(type = SkylarkNestedSet.class),
-            },
-            generic1 = Artifact.class,
-            defaultValue = "[]",
-            doc = "A list or a set of jars that should be used at compilation for a given target."),
-        @Param(
-            name = "runtime_jars",
-            positional = false,
-            named = true,
-            allowedTypes = {
-              @ParamType(type = SkylarkList.class),
-              @ParamType(type = SkylarkNestedSet.class),
-            },
-            generic1 = Artifact.class,
-            defaultValue = "[]",
-            doc = "A list or a set of jars that should be used at runtime for a given target."),
-        @Param(
-            name = "use_ijar",
-            positional = false,
-            named = true,
-            type = Boolean.class,
-            defaultValue = "True",
-            doc =
-                "If True it will generate interface jars for every jar in compile_time_jars."
-                    + "The generating interface jars will be stored as compile_jars "
-                    + "and the initial (full) compile_time_jars will be stored as "
-                    + "full_compile_jars. If False the given compile_jars will be "
-                    + "stored as both compile_jars and full_compile_jars."),
-        @Param(
-            name = "java_toolchain",
-            positional = false,
-            named = true,
-            type = ConfiguredTarget.class,
-            noneable = true,
-            defaultValue = "None",
-            doc =
-                "A label pointing to a java_toolchain rule to be used for retrieving the ijar "
-                    + "tool. Only set when use_ijar is True."),
-        @Param(
-            name = "transitive_compile_time_jars",
-            positional = false,
-            named = true,
-            allowedTypes = {
-              @ParamType(type = SkylarkList.class),
-              @ParamType(type = SkylarkNestedSet.class),
-            },
-            generic1 = Artifact.class,
-            defaultValue = "[]",
-            doc =
-                "A list or set of compile time jars collected from the transitive closure of a "
-                    + "rule."),
-        @Param(
-            name = "transitive_runtime_jars",
-            positional = false,
-            named = true,
-            allowedTypes = {
-              @ParamType(type = SkylarkList.class),
-              @ParamType(type = SkylarkNestedSet.class),
-            },
-            generic1 = Artifact.class,
-            defaultValue = "[]",
-            doc = "A list or set of runtime jars collected from the transitive closure of a rule."),
-        @Param(
-            name = "source_jars",
-            positional = false,
-            named = true,
-            allowedTypes = {
-              @ParamType(type = SkylarkList.class),
-              @ParamType(type = SkylarkNestedSet.class),
-            },
-            generic1 = Artifact.class,
-            defaultValue = "[]",
-            doc =
-                "A list or set of output source jars that contain the uncompiled source files "
-                    + "including the source files generated by annotation processors if the case.")
-      },
-      useLocation = true,
-      useEnvironment = true)
+  @Override
   public JavaInfo create(
       @Nullable Object actionsUnchecked,
       Object compileTimeJars,
@@ -193,147 +78,12 @@ public class JavaSkylarkCommon {
     this.javaSemantics = javaSemantics;
   }
 
-  @SkylarkCallable(
-    name = "provider",
-    structField = true,
-    doc = "Returns the Java declared provider. <br>"
-        + "The same value is accessible as <code>JavaInfo</code>. <br>"
-        + "Prefer using <code>JavaInfo</code> in new code."
-  )
+  @Override
   public Provider getJavaProvider() {
     return JavaInfo.PROVIDER;
   }
 
-  @SkylarkCallable(
-    name = "compile",
-    doc = "Compiles Java source files/jars from the implementation of a Skylark rule and returns a "
-      + "provider that represents the results of the compilation and can be added to the set of "
-      + "providers emitted by this rule.",
-    // There is one mandatory positional: the Skylark rule context.
-    mandatoryPositionals = 1,
-    parameters = {
-      @Param(
-          name = "source_jars",
-          positional = false,
-          named = true,
-          type = SkylarkList.class,
-          generic1 = Artifact.class,
-          defaultValue = "[]",
-          doc = "A list of the jars to be compiled. At least one of source_jars or source_files"
-            + " should be specified."
-      ),
-      @Param(
-        name = "source_files",
-        positional = false,
-        named = true,
-        type = SkylarkList.class,
-        generic1 = Artifact.class,
-        defaultValue = "[]",
-        doc = "A list of the Java source files to be compiled. At least one of source_jars or "
-          + "source_files should be specified."
-      ),
-      @Param(
-        name = "output",
-        positional = false,
-        named = true,
-        type = Artifact.class
-      ),
-      @Param(
-        name = "javac_opts",
-        positional = false,
-        named = true,
-        type = SkylarkList.class,
-        generic1 = String.class,
-        defaultValue =  "[]",
-        doc = "A list of the desired javac options. Optional."
-      ),
-      @Param(
-        name = "deps",
-        positional = false,
-        named = true,
-        type = SkylarkList.class,
-        generic1 = JavaInfo.class,
-        defaultValue = "[]",
-        doc = "A list of dependencies. Optional."
-      ),
-      @Param(
-          name = "exports",
-          positional = false,
-          named = true,
-          type = SkylarkList.class,
-          generic1 = JavaInfo.class,
-          defaultValue = "[]",
-          doc = "A list of exports. Optional."
-      ),
-      @Param(
-          name = "plugins",
-          positional = false,
-          named = true,
-          type = SkylarkList.class,
-          generic1 = JavaInfo.class,
-          defaultValue = "[]",
-          doc = "A list of plugins. Optional."
-      ),
-      @Param(
-          name = "exported_plugins",
-          positional = false,
-          named = true,
-          type = SkylarkList.class,
-          generic1 = JavaInfo.class,
-          defaultValue = "[]",
-          doc = "A list of exported plugins. Optional."
-      ),
-      @Param(
-        name = "strict_deps",
-        defaultValue = "'ERROR'",
-        positional = false,
-        named = true,
-        type = String.class,
-        doc = "A string that specifies how to handle strict deps. Possible values: 'OFF', 'ERROR',"
-          + "'WARN' and 'DEFAULT'. For more details see "
-          + "https://docs.bazel.build/versions/master/bazel-user-manual.html#flag--strict_java_deps"
-          + ". By default 'ERROR'."
-      ),
-      @Param(
-        name = "java_toolchain",
-        positional = false,
-        named = true,
-        type = ConfiguredTarget.class,
-        doc = "A label pointing to a java_toolchain rule to be used for this compilation. "
-          + "Mandatory."
-      ),
-      @Param(
-        name = "host_javabase",
-        positional = false,
-        named = true,
-        type = ConfiguredTarget.class,
-        doc = "A label pointing to a JDK to be used for this compilation. Mandatory."
-      ),
-      @Param(
-        name = "sourcepath",
-        positional = false,
-        named = true,
-        type = SkylarkList.class,
-        generic1 = Artifact.class,
-        defaultValue = "[]"
-      ),
-      @Param(
-          name = "resources",
-          positional = false,
-          named = true,
-          type = SkylarkList.class,
-          generic1 = Artifact.class,
-          defaultValue = "[]"
-      ),
-      @Param(
-          name = "neverlink",
-          positional = false,
-          named = true,
-          type = Boolean.class,
-          defaultValue = "False"
-      )
-    }
-  )
+  @Override
   public JavaInfo createJavaCompileAction(
       SkylarkRuleContext skylarkRuleContext,
       SkylarkList<Artifact> sourceJars,
@@ -371,44 +121,7 @@ public class JavaSkylarkCommon {
             javaSemantics);
   }
 
-  @SkylarkCallable(
-      name = "run_ijar",
-      doc =
-          "Runs ijar on a jar, stripping it of its method bodies. This helps reduce rebuilding "
-              + "of dependent jars during any recompiles consisting only of simple changes to "
-              + "method implementations. The return value is typically passed to "
-              + "<code><a class=\"anchor\" href=\"JavaInfo.html\">"
-              + "JavaInfo</a>#compile_jar</code>.",
-      parameters = {
-        @Param(
-            name = "actions",
-            named = true,
-            type = SkylarkActionFactory.class,
-            doc = "ctx.actions"),
-        @Param(
-            name = "jar",
-            positional = false,
-            named = true,
-            type = Artifact.class,
-            doc = "The jar to run ijar on."),
-        @Param(
-            name = "target_label",
-            positional = false,
-            named = true,
-            type = Label.class,
-            noneable = true,
-            defaultValue = "None",
-            doc =
-                "A target label to stamp the jar with. Used for <code>add_dep</code> support. "
-                    + "Typically, you would pass <code>ctx.label</code> to stamp the jar "
-                    + "with the current rule's label."),
-        @Param(
-            name = "java_toolchain",
-            positional = false,
-            named = true,
-            type = ConfiguredTarget.class,
-            doc = "A label pointing to a java_toolchain rule to used to find the ijar tool."),
-      })
+  @Override
   public Artifact runIjar(
       SkylarkActionFactory actions,
       Artifact jar,
@@ -420,99 +133,14 @@ public class JavaSkylarkCommon {
             actions, jar, targetLabel != Runtime.NONE ? (Label) targetLabel : null, javaToolchain);
   }
 
-  @SkylarkCallable(
-      name = "stamp_jar",
-      doc =
-          "Stamps a jar with a target label for <code>add_dep</code> support. "
-              + "The return value is typically passed to "
-              + "<code><a class=\"anchor\" href=\"JavaInfo.html\">"
-              + "JavaInfo</a>#compile_jar</code>. "
-              + "Prefer to use "
-              + "<code><a class=\"anchor\" href=\"java_common.html#run_ijar\">run_ijar</a></code> "
-              + "when possible.",
-      parameters = {
-        @Param(
-            name = "actions",
-            named = true,
-            type = SkylarkActionFactory.class,
-            doc = "ctx.actions"),
-        @Param(
-            name = "jar",
-            positional = false,
-            named = true,
-            type = Artifact.class,
-            doc = "The jar to run ijar on."),
-        @Param(
-            name = "target_label",
-            positional = false,
-            named = true,
-            type = Label.class,
-            doc =
-                "A target label to stamp the jar with. Used for <code>add_dep</code> support. "
-                    + "Typically, you would pass <code>ctx.label</code> to stamp the jar "
-                    + "with the current rule's label."),
-        @Param(
-            name = "java_toolchain",
-            positional = false,
-            named = true,
-            type = ConfiguredTarget.class,
-            doc = "A label pointing to a java_toolchain rule to used to find the ijar tool."),
-      })
+  @Override
   public Artifact stampJar(
       SkylarkActionFactory actions, Artifact jar, Label targetLabel, ConfiguredTarget javaToolchain)
       throws EvalException {
     return JavaInfoBuildHelper.getInstance().stampJar(actions, jar, targetLabel, javaToolchain);
   }
 
-  @SkylarkCallable(
-      name = "pack_sources",
-      doc =
-          "Packs sources and source jars into a single source jar file. "
-              + "The return value is typically passed to"
-              + "<p><code><a class=\"anchor\" href=\"JavaInfo.html\">"
-              + "JavaInfo</a>#source_jar</code></p>.",
-      parameters = {
-        @Param(
-            name = "actions",
-            named = true,
-            type = SkylarkActionFactory.class,
-            doc = "ctx.actions"),
-        @Param(
-            name = "output_jar",
-            positional = false,
-            named = true,
-            type = Artifact.class,
-            doc = "The output jar of the rule. Used to name the resulting source jar."),
-        @Param(
-            name = "sources",
-            positional = false,
-            named = true,
-            type = SkylarkList.class,
-            generic1 = Artifact.class,
-            defaultValue = "[]",
-            doc = "A list of Java source files to be packed into the source jar."),
-        @Param(
-            name = "source_jars",
-            positional = false,
-            named = true,
-            type = SkylarkList.class,
-            generic1 = Artifact.class,
-            defaultValue = "[]",
-            doc = "A list of source jars to be packed into the source jar."),
-        @Param(
-            name = "java_toolchain",
-            positional = false,
-            named = true,
-            type = ConfiguredTarget.class,
-            doc = "A label pointing to a java_toolchain rule to used to find the ijar tool."),
-        @Param(
-            name = "host_javabase",
-            positional = false,
-            named = true,
-            type = ConfiguredTarget.class,
-            doc = "A label pointing to a JDK to be used for packing sources."),
-      },
-      allowReturnNones = true)
+  @Override
   public Artifact packSources(
       SkylarkActionFactory actions,
       Artifact outputJar,
@@ -525,18 +153,10 @@ public class JavaSkylarkCommon {
         .packSourceFiles(actions, outputJar, sourceFiles, sourceJars, javaToolchain, hostJavabase);
   }
 
-  @SkylarkCallable(
-      name = "default_javac_opts",
-      // This function is experimental for now.
-      documented = false,
-      // There's only one mandatory positional,the Skylark context
-      mandatoryPositionals = 1,
-      parameters = {
-        @Param(name = "java_toolchain_attr", positional = false, named = true, type = String.class)
-      })
+  @Override
   // TODO(b/78512644): migrate callers to passing explicit javacopts or using custom toolchains, and
   // delete
-  public static ImmutableList<String> getDefaultJavacOpts(
+  public ImmutableList<String> getDefaultJavacOpts(
       SkylarkRuleContext skylarkRuleContext, String javaToolchainAttr) throws EvalException {
     RuleContext ruleContext = skylarkRuleContext.getRuleContext();
     ConfiguredTarget javaToolchainConfigTarget =
@@ -556,26 +176,14 @@ public class JavaSkylarkCommon {
         javacOptsFromAttr));
   }
 
-  @SkylarkCallable(
-    name = "merge",
-    doc = "Merges the given providers into a single JavaInfo.",
-    // We have one positional argument: the list of providers to merge.
-    mandatoryPositionals = 1
-  )
-  public static JavaInfo mergeJavaProviders(SkylarkList<JavaInfo> providers) {
+  @Override
+  public JavaInfo mergeJavaProviders(SkylarkList<JavaInfo> providers) {
     return JavaInfo.merge(providers);
   }
 
   // TODO(b/65113771): Remove this method because it's incorrect.
-  @SkylarkCallable(
-    name = "make_non_strict",
-    doc =
-        "Returns a new Java provider whose direct-jars part is the union of both the direct and"
-            + " indirect jars of the given Java provider.",
-    // There's only one mandatory positional, the Java provider.
-    mandatoryPositionals = 1
-  )
-  public static JavaInfo makeNonStrict(JavaInfo javaInfo) {
+  @Override
+  public JavaInfo makeNonStrict(JavaInfo javaInfo) {
     JavaCompilationArgsProvider directCompilationArgs =
         makeNonStrict(javaInfo.getProvider(JavaCompilationArgsProvider.class));
 
@@ -601,14 +209,8 @@ public class JavaSkylarkCommon {
         provider.getCompileTimeJavaDependencyArtifacts());
   }
 
-  @SkylarkCallable(
-    name = JavaRuntimeInfo.SKYLARK_NAME,
-    doc =
-        "The key used to retrieve the provider that contains information about the Java "
-            + "runtime being used.",
-    structField = true
-  )
-  public static Provider getJavaRuntimeProvider() {
+  @Override
+  public Provider getJavaRuntimeProvider() {
     return JavaRuntimeInfo.PROVIDER;
   }
 
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/JavaToolchainSkylarkApiProvider.java b/src/main/java/com/google/devtools/build/lib/rules/java/JavaToolchainSkylarkApiProvider.java
index 0d9347227b..28937063ca 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/java/JavaToolchainSkylarkApiProvider.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/JavaToolchainSkylarkApiProvider.java
@@ -17,28 +17,22 @@ package com.google.devtools.build.lib.rules.java;
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.analysis.skylark.SkylarkApiProvider;
 import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec;
-import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
-import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
+import com.google.devtools.build.lib.skylarkbuildapi.java.JavaToolchainSkylarkApiProviderApi;
 import java.util.Iterator;
 
 /**
  * A class that exposes the java_toolchain providers to Skylark. It is intended to provide a simple
  * and stable interface for Skylark users.
  */
-@SkylarkModule(
-  name = "JavaToolchainSkylarkApiProvider",
-  doc =
-      "Provides access to information about the Java toolchain rule. "
-          + "Accessible as a 'java_toolchain' field on a Target struct."
-)
 @AutoCodec
-public final class JavaToolchainSkylarkApiProvider extends SkylarkApiProvider {
+public final class JavaToolchainSkylarkApiProvider extends SkylarkApiProvider
+    implements JavaToolchainSkylarkApiProviderApi {
   /** The name of the field in Skylark used to access this class. */
   public static final String NAME = "java_toolchain";
 
   /** @return the input Java language level */
   // TODO(cushon): remove this API; it bakes a deprecated detail of the javac API into Bazel
-  @SkylarkCallable(name = "source_version", doc = "The java source version.", structField = true)
+  @Override
   public String getSourceVersion() {
     JavaToolchainProvider javaToolchainProvider =
         JavaToolchainProvider.from(getInfo());
@@ -53,7 +47,7 @@ public final class JavaToolchainSkylarkApiProvider extends SkylarkApiProvider {
 
   /** @return the target Java language level */
   // TODO(cushon): remove this API; it bakes a deprecated detail of the javac API into Bazel
-  @SkylarkCallable(name = "target_version", doc = "The java target version.", structField = true)
+  @Override
   public String getTargetVersion() {
     JavaToolchainProvider javaToolchainProvider =
         JavaToolchainProvider.from(getInfo());
@@ -67,11 +61,7 @@ public final class JavaToolchainSkylarkApiProvider extends SkylarkApiProvider {
   }
 
   /** @return The {@link Artifact} of the javac jar */
-  @SkylarkCallable(
-      name = "javac_jar",
-      doc = "The javac jar.",
-      structField = true
-  )
+  @Override
   public Artifact getJavacJar() {
     JavaToolchainProvider javaToolchainProvider =
         JavaToolchainProvider.from(getInfo());
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/proto/JavaProtoSkylarkCommon.java b/src/main/java/com/google/devtools/build/lib/rules/java/proto/JavaProtoSkylarkCommon.java
index 6ec3fcfd0a..cbd866a72f 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/java/proto/JavaProtoSkylarkCommon.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/proto/JavaProtoSkylarkCommon.java
@@ -28,45 +28,16 @@ import com.google.devtools.build.lib.rules.proto.ProtoCompileActionBuilder;
 import com.google.devtools.build.lib.rules.proto.ProtoLangToolchainProvider;
 import com.google.devtools.build.lib.rules.proto.ProtoSupportDataProvider;
 import com.google.devtools.build.lib.rules.proto.SupportData;
-import com.google.devtools.build.lib.skylarkinterface.Param;
-import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
-import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
+import com.google.devtools.build.lib.skylarkbuildapi.java.JavaProtoCommonApi;
 import com.google.devtools.build.lib.syntax.EvalException;
 
 /**
  * A class that exposes Java common methods for proto compilation.
  */
-@SkylarkModule(name = "java_proto_common", doc = "Helper class for Java proto compilation.")
-public class JavaProtoSkylarkCommon {
-  @SkylarkCallable(
-      name = "create_java_lite_proto_compile_action",
-      // This function is experimental for now.
-      documented = false,
-      // There's 2 mandatory positional arguments, the Skylark context and the ConfiguredTarget.
-      mandatoryPositionals = 2,
-      parameters = {
-          @Param(
-              name = "src_jar",
-              positional = false,
-              named = true,
-              type = Artifact.class
-          ),
-          @Param(
-              name = "proto_toolchain_attr",
-              positional = false,
-              named = true,
-              type = String.class
-          ),
-          @Param(
-              name = "flavour",
-              positional = false,
-              named = true,
-              type = String.class,
-              defaultValue = "java"
-          )
-      }
-  )
-  public static void createProtoCompileAction(
+public class JavaProtoSkylarkCommon
+    implements JavaProtoCommonApi<Artifact, SkylarkRuleContext, ConfiguredTarget> {
+  @Override
+  public void createProtoCompileAction(
       SkylarkRuleContext skylarkRuleContext,
       ConfiguredTarget target,
       Artifact sourceJar,
@@ -91,29 +62,15 @@ public class JavaProtoSkylarkCommon {
         /* allowServices= */ true);
   }
 
-  @SkylarkCallable(
-      name = "has_proto_sources",
-      doc = "Returns whether the given proto_library target contains proto sources. If there are no"
-          + " sources it means that the proto_library is an alias library, which exports its"
-          + " dependencies."
-  )
-  public static boolean hasProtoSources(ConfiguredTarget target) {
+  @Override
+  public boolean hasProtoSources(ConfiguredTarget target) {
     SupportData supportData =
         checkNotNull(target.getProvider(ProtoSupportDataProvider.class).getSupportData());
     return supportData.hasProtoSources();
   }
 
-  @SkylarkCallable(
-    name = "toolchain_deps",
-    // This function is experimental for now.
-    documented = false,
-    // There's only one mandatory positional,the Skylark context
-    mandatoryPositionals = 1,
-    parameters = {
-      @Param(name = "proto_toolchain_attr", positional = false, named = true, type = String.class)
-    }
-  )
-  public static JavaInfo getRuntimeToolchainProvider(
+  @Override
+  public JavaInfo getRuntimeToolchainProvider(
       SkylarkRuleContext skylarkRuleContext, String protoToolchainAttr) throws EvalException {
     TransitiveInfoCollection runtime =
         getProtoToolchainProvider(skylarkRuleContext, protoToolchainAttr).runtime();
@@ -125,19 +82,10 @@ public class JavaProtoSkylarkCommon {
             .build();
   }
 
-  @SkylarkCallable(
-    name = "javac_opts",
-    // This function is experimental for now.
-    documented = false,
-    // There's only one mandatory positional,the Skylark context
-    mandatoryPositionals = 1,
-    parameters = {
-      @Param(name = "java_toolchain_attr", positional = false, named = true, type = String.class)
-    }
-  )
+  @Override
   // TODO(b/78512644): migrate callers to passing explicit proto javacopts or using custom
   // toolchains, and delete
-  public static ImmutableList<String> getJavacOpts(
+  public ImmutableList<String> getJavacOpts(
       SkylarkRuleContext skylarkRuleContext, String javaToolchainAttr) throws EvalException {
     ConfiguredTarget javaToolchainConfigTarget =
         (ConfiguredTarget) checkNotNull(skylarkRuleContext.getAttr().getValue(javaToolchainAttr));
diff --git a/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/BUILD b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/BUILD
index 59948ecfe6..938435abf6 100644
--- a/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/BUILD
+++ b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/BUILD
@@ -25,6 +25,7 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib/cmdline",
         "//src/main/java/com/google/devtools/build/lib/collect/nestedset",
         "//src/main/java/com/google/devtools/build/lib/skylarkbuildapi",
+        "//src/main/java/com/google/devtools/build/lib/vfs:pathfragment",
         "//third_party:guava",
         "//third_party:jsr305",
     ],
diff --git a/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/JavaCommonApi.java b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/JavaCommonApi.java
new file mode 100644
index 0000000000..79c9b0a2cd
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/JavaCommonApi.java
@@ -0,0 +1,512 @@
+// Copyright 2018 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.devtools.build.lib.skylarkbuildapi.java;
+
+import com.google.common.collect.ImmutableList;
+import com.google.devtools.build.lib.cmdline.Label;
+import com.google.devtools.build.lib.events.Location;
+import com.google.devtools.build.lib.skylarkbuildapi.FileApi;
+import com.google.devtools.build.lib.skylarkbuildapi.ProviderApi;
+import com.google.devtools.build.lib.skylarkbuildapi.SkylarkActionFactoryApi;
+import com.google.devtools.build.lib.skylarkbuildapi.SkylarkRuleContextApi;
+import com.google.devtools.build.lib.skylarkbuildapi.TransitiveInfoCollectionApi;
+import com.google.devtools.build.lib.skylarkinterface.Param;
+import com.google.devtools.build.lib.skylarkinterface.ParamType;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
+import com.google.devtools.build.lib.syntax.Environment;
+import com.google.devtools.build.lib.syntax.EvalException;
+import com.google.devtools.build.lib.syntax.SkylarkList;
+import com.google.devtools.build.lib.syntax.SkylarkNestedSet;
+import javax.annotation.Nullable;
+
+/**
+ * Utilities for Java compilation support in Skylark.
+ */
+@SkylarkModule(name = "java_common", doc = "Utilities for Java compilation support in Skylark.")
+public interface JavaCommonApi<FileT extends FileApi, JavaInfoT extends JavaInfoApi<FileT>,
+    SkylarkRuleContextT extends SkylarkRuleContextApi,
+    TransitiveInfoCollectionT extends TransitiveInfoCollectionApi,
+    SkylarkActionFactoryT extends SkylarkActionFactoryApi> {
+
+  @SkylarkCallable(
+      name = "create_provider",
+      doc =
+          "Creates a JavaInfo from jars. compile_time/runtime_jars represent the outputs of the "
+              + "target providing a JavaInfo, while transitive_*_jars represent their dependencies."
+              + "<p>Note: compile_time_jars and runtime_jars are not automatically merged into the "
+              + "transitive jars (unless the given transitive_*_jars are empty) - if this is the "
+              + "desired behaviour the user should merge the jars before creating the provider."
+              + "<p>This function also creates actions to generate interface jars by default."
+              + "<p>When use_ijar is True, ijar will be run on the given compile_time_jars and the "
+              + "resulting interface jars will be stored as compile_jars, "
+              + "while the initial jars will be stored as full_compile_jars. "
+              + "<p>When use_ijar=False, the given compile_time_jars will be stored as both "
+              + "compile_jars and full_compile_jars. No actions are created. "
+              + "See JavaInfo#compile_jars and JavaInfo#full_compile_jars for more details."
+              + "<p>Currently only "
+              + "<a href='https://github.com/bazelbuild/bazel/tree/master/third_party/ijar'>"
+              + "ijar</a>"
+              + " is supported for generating interface jars. "
+              + "Header compilation is not yet supported.",
+      parameters = {
+        @Param(
+            name = "actions",
+            type = SkylarkActionFactoryApi.class,
+            noneable = true,
+            defaultValue = "None",
+            doc =
+                "The ctx.actions object, used to register the actions for creating the "
+                    + "interface jars. Only set if use_ijar=True."),
+        @Param(
+            name = "compile_time_jars",
+            positional = false,
+            named = true,
+            allowedTypes = {
+              @ParamType(type = SkylarkList.class),
+              @ParamType(type = SkylarkNestedSet.class),
+            },
+            generic1 = FileApi.class,
+            defaultValue = "[]",
+            doc = "A list or a set of jars that should be used at compilation for a given target."),
+        @Param(
+            name = "runtime_jars",
+            positional = false,
+            named = true,
+            allowedTypes = {
+              @ParamType(type = SkylarkList.class),
+              @ParamType(type = SkylarkNestedSet.class),
+            },
+            generic1 = FileApi.class,
+            defaultValue = "[]",
+            doc = "A list or a set of jars that should be used at runtime for a given target."),
+        @Param(
+            name = "use_ijar",
+            positional = false,
+            named = true,
+            type = Boolean.class,
+            defaultValue = "True",
+            doc =
+                "If True it will generate interface jars for every jar in compile_time_jars."
+                    + "The generating interface jars will be stored as compile_jars "
+                    + "and the initial (full) compile_time_jars will be stored as "
+                    + "full_compile_jars. If False the given compile_jars will be "
+                    + "stored as both compile_jars and full_compile_jars."),
+        @Param(
+            name = "java_toolchain",
+            positional = false,
+            named = true,
+            type = TransitiveInfoCollectionApi.class,
+            noneable = true,
+            defaultValue = "None",
+            doc =
+                "A label pointing to a java_toolchain rule to be used for retrieving the ijar "
+                    + "tool. Only set when use_ijar is True."),
+        @Param(
+            name = "transitive_compile_time_jars",
+            positional = false,
+            named = true,
+            allowedTypes = {
+              @ParamType(type = SkylarkList.class),
+              @ParamType(type = SkylarkNestedSet.class),
+            },
+            generic1 = FileApi.class,
+            defaultValue = "[]",
+            doc =
+                "A list or set of compile time jars collected from the transitive closure of a "
+                    + "rule."),
+        @Param(
+            name = "transitive_runtime_jars",
+            positional = false,
+            named = true,
+            allowedTypes = {
+              @ParamType(type = SkylarkList.class),
+              @ParamType(type = SkylarkNestedSet.class),
+            },
+            generic1 = FileApi.class,
+            defaultValue = "[]",
+            doc = "A list or set of runtime jars collected from the transitive closure of a rule."),
+        @Param(
+            name = "source_jars",
+            positional = false,
+            named = true,
+            allowedTypes = {
+              @ParamType(type = SkylarkList.class),
+              @ParamType(type = SkylarkNestedSet.class),
+            },
+            generic1 = FileApi.class,
+            defaultValue = "[]",
+            doc =
+                "A list or set of output source jars that contain the uncompiled source files "
+                    + "including the source files generated by annotation processors if the case.")
+      },
+      useLocation = true,
+      useEnvironment = true)
+  public JavaInfoT create(
+      @Nullable Object actionsUnchecked,
+      Object compileTimeJars,
+      Object runtimeJars,
+      Boolean useIjar,
+      @Nullable Object javaToolchainUnchecked,
+      Object transitiveCompileTimeJars,
+      Object transitiveRuntimeJars,
+      Object sourceJars,
+      Location location,
+      Environment environment)
+      throws EvalException;
+
+  @SkylarkCallable(
+    name = "provider",
+    structField = true,
+    doc = "Returns the Java declared provider. <br>"
+        + "The same value is accessible as <code>JavaInfo</code>. <br>"
+        + "Prefer using <code>JavaInfo</code> in new code."
+  )
+  public ProviderApi getJavaProvider();
+
+  @SkylarkCallable(
+    name = "compile",
+    doc = "Compiles Java source files/jars from the implementation of a Skylark rule and returns a "
+      + "provider that represents the results of the compilation and can be added to the set of "
+      + "providers emitted by this rule.",
+    // There is one mandatory positional: the Skylark rule context.
+    mandatoryPositionals = 1,
+    parameters = {
+      @Param(
+          name = "source_jars",
+          positional = false,
+          named = true,
+          type = SkylarkList.class,
+          generic1 = FileApi.class,
+          defaultValue = "[]",
+          doc = "A list of the jars to be compiled. At least one of source_jars or source_files"
+            + " should be specified."
+      ),
+      @Param(
+        name = "source_files",
+        positional = false,
+        named = true,
+        type = SkylarkList.class,
+        generic1 = FileApi.class,
+        defaultValue = "[]",
+        doc = "A list of the Java source files to be compiled. At least one of source_jars or "
+          + "source_files should be specified."
+      ),
+      @Param(
+        name = "output",
+        positional = false,
+        named = true,
+        type = FileApi.class
+      ),
+      @Param(
+        name = "javac_opts",
+        positional = false,
+        named = true,
+        type = SkylarkList.class,
+        generic1 = String.class,
+        defaultValue =  "[]",
+        doc = "A list of the desired javac options. Optional."
+      ),
+      @Param(
+        name = "deps",
+        positional = false,
+        named = true,
+        type = SkylarkList.class,
+        generic1 = JavaInfoApi.class,
+        defaultValue = "[]",
+        doc = "A list of dependencies. Optional."
+      ),
+      @Param(
+          name = "exports",
+          positional = false,
+          named = true,
+          type = SkylarkList.class,
+          generic1 = JavaInfoApi.class,
+          defaultValue = "[]",
+          doc = "A list of exports. Optional."
+      ),
+      @Param(
+          name = "plugins",
+          positional = false,
+          named = true,
+          type = SkylarkList.class,
+          generic1 = JavaInfoApi.class,
+          defaultValue = "[]",
+          doc = "A list of plugins. Optional."
+      ),
+      @Param(
+          name = "exported_plugins",
+          positional = false,
+          named = true,
+          type = SkylarkList.class,
+          generic1 = JavaInfoApi.class,
+          defaultValue = "[]",
+          doc = "A list of exported plugins. Optional."
+      ),
+      @Param(
+        name = "strict_deps",
+        defaultValue = "'ERROR'",
+        positional = false,
+        named = true,
+        type = String.class,
+        doc = "A string that specifies how to handle strict deps. Possible values: 'OFF', 'ERROR',"
+          + "'WARN' and 'DEFAULT'. For more details see "
+          + "https://docs.bazel.build/versions/master/bazel-user-manual.html#flag--strict_java_deps"
+          + ". By default 'ERROR'."
+      ),
+      @Param(
+        name = "java_toolchain",
+        positional = false,
+        named = true,
+        type = TransitiveInfoCollectionApi.class,
+        doc = "A label pointing to a java_toolchain rule to be used for this compilation. "
+          + "Mandatory."
+      ),
+      @Param(
+        name = "host_javabase",
+        positional = false,
+        named = true,
+        type = TransitiveInfoCollectionApi.class,
+        doc = "A label pointing to a JDK to be used for this compilation. Mandatory."
+      ),
+      @Param(
+        name = "sourcepath",
+        positional = false,
+        named = true,
+        type = SkylarkList.class,
+        generic1 = FileApi.class,
+        defaultValue = "[]"
+      ),
+      @Param(
+          name = "resources",
+          positional = false,
+          named = true,
+          type = SkylarkList.class,
+          generic1 = FileApi.class,
+          defaultValue = "[]"
+      ),
+      @Param(
+          name = "neverlink",
+          positional = false,
+          named = true,
+          type = Boolean.class,
+          defaultValue = "False"
+      )
+    }
+  )
+  public JavaInfoT createJavaCompileAction(
+      SkylarkRuleContextT skylarkRuleContext,
+      SkylarkList<FileT> sourceJars,
+      SkylarkList<FileT> sourceFiles,
+      FileT outputJar,
+      SkylarkList<String> javacOpts,
+      SkylarkList<JavaInfoT> deps,
+      SkylarkList<JavaInfoT> exports,
+      SkylarkList<JavaInfoT> plugins,
+      SkylarkList<JavaInfoT> exportedPlugins,
+      String strictDepsMode,
+      TransitiveInfoCollectionT javaToolchain,
+      TransitiveInfoCollectionT hostJavabase,
+      SkylarkList<FileT> sourcepathEntries,
+      SkylarkList<FileT> resources,
+      Boolean neverlink) throws EvalException, InterruptedException;
+
+  @SkylarkCallable(
+      name = "run_ijar",
+      doc =
+          "Runs ijar on a jar, stripping it of its method bodies. This helps reduce rebuilding "
+              + "of dependent jars during any recompiles consisting only of simple changes to "
+              + "method implementations. The return value is typically passed to "
+              + "<code><a class=\"anchor\" href=\"JavaInfo.html\">"
+              + "JavaInfo</a>#compile_jar</code>.",
+      parameters = {
+        @Param(
+            name = "actions",
+            named = true,
+            type = SkylarkActionFactoryApi.class,
+            doc = "ctx.actions"),
+        @Param(
+            name = "jar",
+            positional = false,
+            named = true,
+            type = FileApi.class,
+            doc = "The jar to run ijar on."),
+        @Param(
+            name = "target_label",
+            positional = false,
+            named = true,
+            type = Label.class,
+            noneable = true,
+            defaultValue = "None",
+            doc =
+                "A target label to stamp the jar with. Used for <code>add_dep</code> support. "
+                    + "Typically, you would pass <code>ctx.label</code> to stamp the jar "
+                    + "with the current rule's label."),
+        @Param(
+            name = "java_toolchain",
+            positional = false,
+            named = true,
+            type = TransitiveInfoCollectionApi.class,
+            doc = "A label pointing to a java_toolchain rule to used to find the ijar tool."),
+      })
+  public FileApi runIjar(
+      SkylarkActionFactoryT actions,
+      FileT jar,
+      Object targetLabel,
+      TransitiveInfoCollectionT javaToolchain)
+      throws EvalException;
+
+  @SkylarkCallable(
+      name = "stamp_jar",
+      doc =
+          "Stamps a jar with a target label for <code>add_dep</code> support. "
+              + "The return value is typically passed to "
+              + "<code><a class=\"anchor\" href=\"JavaInfo.html\">"
+              + "JavaInfo</a>#compile_jar</code>. "
+              + "Prefer to use "
+              + "<code><a class=\"anchor\" href=\"java_common.html#run_ijar\">run_ijar</a></code> "
+              + "when possible.",
+      parameters = {
+        @Param(
+            name = "actions",
+            named = true,
+            type = SkylarkActionFactoryApi.class,
+            doc = "ctx.actions"),
+        @Param(
+            name = "jar",
+            positional = false,
+            named = true,
+            type = FileApi.class,
+            doc = "The jar to run ijar on."),
+        @Param(
+            name = "target_label",
+            positional = false,
+            named = true,
+            type = Label.class,
+            doc =
+                "A target label to stamp the jar with. Used for <code>add_dep</code> support. "
+                    + "Typically, you would pass <code>ctx.label</code> to stamp the jar "
+                    + "with the current rule's label."),
+        @Param(
+            name = "java_toolchain",
+            positional = false,
+            named = true,
+            type = TransitiveInfoCollectionApi.class,
+            doc = "A label pointing to a java_toolchain rule to used to find the ijar tool."),
+      })
+  public FileApi stampJar(
+      SkylarkActionFactoryT actions, FileT jar, Label targetLabel,
+      TransitiveInfoCollectionT javaToolchain)
+      throws EvalException;
+
+  @SkylarkCallable(
+      name = "pack_sources",
+      doc =
+          "Packs sources and source jars into a single source jar file. "
+              + "The return value is typically passed to"
+              + "<p><code><a class=\"anchor\" href=\"JavaInfo.html\">"
+              + "JavaInfo</a>#source_jar</code></p>.",
+      parameters = {
+        @Param(
+            name = "actions",
+            named = true,
+            type = SkylarkActionFactoryApi.class,
+            doc = "ctx.actions"),
+        @Param(
+            name = "output_jar",
+            positional = false,
+            named = true,
+            type = FileApi.class,
+            doc = "The output jar of the rule. Used to name the resulting source jar."),
+        @Param(
+            name = "sources",
+            positional = false,
+            named = true,
+            type = SkylarkList.class,
+            generic1 = FileApi.class,
+            defaultValue = "[]",
+            doc = "A list of Java source files to be packed into the source jar."),
+        @Param(
+            name = "source_jars",
+            positional = false,
+            named = true,
+            type = SkylarkList.class,
+            generic1 = FileApi.class,
+            defaultValue = "[]",
+            doc = "A list of source jars to be packed into the source jar."),
+        @Param(
+            name = "java_toolchain",
+            positional = false,
+            named = true,
+            type = TransitiveInfoCollectionApi.class,
+            doc = "A label pointing to a java_toolchain rule to used to find the ijar tool."),
+        @Param(
+            name = "host_javabase",
+            positional = false,
+            named = true,
+            type = TransitiveInfoCollectionApi.class,
+            doc = "A label pointing to a JDK to be used for packing sources."),
+      },
+      allowReturnNones = true)
+  public FileApi packSources(
+      SkylarkActionFactoryT actions,
+      FileT outputJar,
+      SkylarkList<FileT> sourceFiles,
+      SkylarkList<FileT> sourceJars,
+      TransitiveInfoCollectionT javaToolchain,
+      TransitiveInfoCollectionT hostJavabase)
+      throws EvalException;
+
+  @SkylarkCallable(
+      name = "default_javac_opts",
+      // This function is experimental for now.
+      documented = false,
+      // There's only one mandatory positional,the Skylark context
+      mandatoryPositionals = 1,
+      parameters = {
+        @Param(name = "java_toolchain_attr", positional = false, named = true, type = String.class)
+      })
+  // TODO(b/78512644): migrate callers to passing explicit javacopts or using custom toolchains, and
+  // delete
+  public ImmutableList<String> getDefaultJavacOpts(
+      SkylarkRuleContextT skylarkRuleContext, String javaToolchainAttr) throws EvalException;
+
+  @SkylarkCallable(
+    name = "merge",
+    doc = "Merges the given providers into a single JavaInfo.",
+    // We have one positional argument: the list of providers to merge.
+    mandatoryPositionals = 1
+  )
+  public JavaInfoT mergeJavaProviders(SkylarkList<JavaInfoT> providers);
+
+  @SkylarkCallable(
+    name = "make_non_strict",
+    doc =
+        "Returns a new Java provider whose direct-jars part is the union of both the direct and"
+            + " indirect jars of the given Java provider.",
+    // There's only one mandatory positional, the Java provider.
+    mandatoryPositionals = 1
+  )
+  public JavaInfoT makeNonStrict(JavaInfoT javaInfo);
+
+  @SkylarkCallable(
+    name = "JavaRuntimeInfo",
+    doc =
+        "The key used to retrieve the provider that contains information about the Java "
+            + "runtime being used.",
+    structField = true
+  )
+  public ProviderApi getJavaRuntimeProvider();
+}
diff --git a/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/JavaConfigurationApi.java b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/JavaConfigurationApi.java
new file mode 100644
index 0000000000..eafb90e4bd
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/JavaConfigurationApi.java
@@ -0,0 +1,44 @@
+// Copyright 2018 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.devtools.build.lib.skylarkbuildapi.java;
+
+import com.google.common.collect.ImmutableList;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkModuleCategory;
+
+/**
+ * A java compiler configuration.
+ */
+@SkylarkModule(
+    name = "java",
+    doc = "A java compiler configuration.",
+    category = SkylarkModuleCategory.CONFIGURATION_FRAGMENT
+)
+public interface JavaConfigurationApi {
+
+  @SkylarkCallable(name = "default_javac_flags", structField = true,
+      doc = "The default flags for the Java compiler.")
+  // TODO(bazel-team): this is the command-line passed options, we should remove from skylark
+  // probably.
+  public ImmutableList<String> getDefaultJavacFlags();
+
+  @SkylarkCallable(
+      name = "strict_java_deps",
+      structField = true,
+      doc = "The value of the strict_java_deps flag."
+  )
+  public String getStrictJavaDepsName();
+}
diff --git a/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/JavaProtoCommonApi.java b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/JavaProtoCommonApi.java
new file mode 100644
index 0000000000..3afc99ec0c
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/JavaProtoCommonApi.java
@@ -0,0 +1,104 @@
+// Copyright 2018 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.devtools.build.lib.skylarkbuildapi.java;
+
+import com.google.common.collect.ImmutableList;
+import com.google.devtools.build.lib.skylarkbuildapi.FileApi;
+import com.google.devtools.build.lib.skylarkbuildapi.SkylarkRuleContextApi;
+import com.google.devtools.build.lib.skylarkbuildapi.TransitiveInfoCollectionApi;
+import com.google.devtools.build.lib.skylarkinterface.Param;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
+import com.google.devtools.build.lib.syntax.EvalException;
+
+/**
+ * Helper class for Java proto compilation.
+ */
+@SkylarkModule(name = "java_proto_common", doc = "Helper class for Java proto compilation.")
+public interface JavaProtoCommonApi<FileT extends FileApi,
+    SkylarkRuleContextT extends SkylarkRuleContextApi,
+    TransitiveInfoCollectionT extends TransitiveInfoCollectionApi> {
+
+  @SkylarkCallable(
+      name = "create_java_lite_proto_compile_action",
+      // This function is experimental for now.
+      documented = false,
+      // There's 2 mandatory positional arguments, the Skylark context and the ConfiguredTarget.
+      mandatoryPositionals = 2,
+      parameters = {
+          @Param(
+              name = "src_jar",
+              positional = false,
+              named = true,
+              type = FileApi.class
+          ),
+          @Param(
+              name = "proto_toolchain_attr",
+              positional = false,
+              named = true,
+              type = String.class
+          ),
+          @Param(
+              name = "flavour",
+              positional = false,
+              named = true,
+              type = String.class,
+              defaultValue = "java"
+          )
+      }
+  )
+  public void createProtoCompileAction(
+      SkylarkRuleContextT skylarkRuleContext,
+      TransitiveInfoCollectionT target,
+      FileT sourceJar,
+      String protoToolchainAttr,
+      String flavour) throws EvalException;
+
+  @SkylarkCallable(
+      name = "has_proto_sources",
+      doc = "Returns whether the given proto_library target contains proto sources. If there are no"
+          + " sources it means that the proto_library is an alias library, which exports its"
+          + " dependencies."
+  )
+  public boolean hasProtoSources(TransitiveInfoCollectionT target);
+
+  @SkylarkCallable(
+    name = "toolchain_deps",
+    // This function is experimental for now.
+    documented = false,
+    // There's only one mandatory positional,the Skylark context
+    mandatoryPositionals = 1,
+    parameters = {
+      @Param(name = "proto_toolchain_attr", positional = false, named = true, type = String.class)
+    }
+  )
+  public JavaInfoApi<FileT> getRuntimeToolchainProvider(
+      SkylarkRuleContextT skylarkRuleContext, String protoToolchainAttr) throws EvalException;
+
+  @SkylarkCallable(
+    name = "javac_opts",
+    // This function is experimental for now.
+    documented = false,
+    // There's only one mandatory positional,the Skylark context
+    mandatoryPositionals = 1,
+    parameters = {
+      @Param(name = "java_toolchain_attr", positional = false, named = true, type = String.class)
+    }
+  )
+  // TODO(b/78512644): migrate callers to passing explicit proto javacopts or using custom
+  // toolchains, and delete
+  public ImmutableList<String> getJavacOpts(
+      SkylarkRuleContextT skylarkRuleContext, String javaToolchainAttr) throws EvalException;
+}
diff --git a/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/JavaRuntimeClasspathProviderApi.java b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/JavaRuntimeClasspathProviderApi.java
new file mode 100644
index 0000000000..8d625ed44d
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/JavaRuntimeClasspathProviderApi.java
@@ -0,0 +1,30 @@
+// Copyright 2018 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.devtools.build.lib.skylarkbuildapi.java;
+
+import com.google.devtools.build.lib.collect.nestedset.NestedSet;
+import com.google.devtools.build.lib.skylarkbuildapi.FileApi;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
+
+/**
+ * Provider for the runtime classpath contributions of a Java binary.
+ */
+@SkylarkModule(name = "JavaRuntimeClasspathProvider", doc = "", documented = false)
+public interface JavaRuntimeClasspathProviderApi<FileT extends FileApi> {
+
+  @SkylarkCallable(name = "runtime_classpath", documented = false, structField = true)
+  public NestedSet<FileT> getRuntimeClasspath();
+}
diff --git a/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/JavaRuntimeInfoApi.java b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/JavaRuntimeInfoApi.java
new file mode 100644
index 0000000000..bea3b41801
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/JavaRuntimeInfoApi.java
@@ -0,0 +1,53 @@
+// Copyright 2018 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.devtools.build.lib.skylarkbuildapi.java;
+
+import com.google.devtools.build.lib.skylarkbuildapi.StructApi;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
+import com.google.devtools.build.lib.vfs.PathFragment;
+
+/**
+ * Information about the Java runtime being used.
+ */
+@SkylarkModule(name = "JavaRuntimeInfo", doc = "Information about the Java runtime being used.")
+public interface JavaRuntimeInfoApi extends StructApi {
+
+  @SkylarkCallable(
+      name = "java_home",
+      doc = "Returns the execpath of the root of the Java installation.",
+      structField = true
+  )
+  public PathFragment javaHome();
+
+  @SkylarkCallable(
+      name = "java_executable_exec_path",
+      doc = "Returns the execpath of the Java executable.",
+      structField = true
+  )
+  /** The execpath of the Java binary. */
+  public PathFragment javaBinaryExecPath();
+
+  @SkylarkCallable(
+      name = "java_executable_runfiles_path",
+      doc = "Returns the path of the Java executable in runfiles trees. This should only be used "
+          + "when one needs to access the JVM during the execution of a binary or a test built "
+          + "by Bazel. In particular, when one needs to invoke the JVM during an action, "
+          + "java_executable_exec_path should be used instead.",
+      structField = true
+  )
+  /** The runfiles path of the Java binary. */
+  public PathFragment javaBinaryRunfilesPath();
+}
diff --git a/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/JavaSkylarkApiProviderApi.java b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/JavaSkylarkApiProviderApi.java
new file mode 100644
index 0000000000..6afac7e8aa
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/JavaSkylarkApiProviderApi.java
@@ -0,0 +1,98 @@
+// Copyright 2018 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.devtools.build.lib.skylarkbuildapi.java;
+
+import com.google.devtools.build.lib.cmdline.Label;
+import com.google.devtools.build.lib.collect.nestedset.NestedSet;
+import com.google.devtools.build.lib.skylarkbuildapi.FileApi;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkModuleCategory;
+
+/**
+ * Provides access to information about Java rules. Every Java-related target provides
+ * this struct, accessible as a java field on a Target.
+ */
+@SkylarkModule(
+    name = "JavaSkylarkApiProvider",
+    title = "java",
+    category = SkylarkModuleCategory.PROVIDER,
+    doc =
+        "Provides access to information about Java rules. Every Java-related target provides "
+            + "this struct, accessible as a <code>java</code> field on a "
+            + "<a href=\"Target.html\">target</a>."
+)
+public interface JavaSkylarkApiProviderApi<FileT extends FileApi> {
+
+  @SkylarkCallable(
+    name = "source_jars",
+    doc = "Returns the Jars containing Java source files for the target.",
+    structField = true
+  )
+  public NestedSet<FileT> getSourceJars();
+
+  @SkylarkCallable(
+    name = "transitive_deps",
+    doc = "Returns the transitive set of Jars required to build the target.",
+    structField = true
+  )
+  public NestedSet<FileT> getTransitiveDeps();
+
+  @SkylarkCallable(
+    name = "transitive_runtime_deps",
+    doc = "Returns the transitive set of Jars required on the target's runtime classpath.",
+    structField = true
+  )
+  public NestedSet<FileT> getTransitiveRuntimeDeps();
+
+  @SkylarkCallable(
+    name = "transitive_source_jars",
+    doc =
+        "Returns the Jars containing Java source files for the target and all of its transitive "
+            + "dependencies.",
+    structField = true
+  )
+  public NestedSet<FileT> getTransitiveSourceJars();
+
+  @SkylarkCallable(
+    name = "outputs",
+    doc = "Returns information about outputs of this Java target.",
+    structField = true
+  )
+  public JavaRuleOutputJarsProviderApi<?> getOutputJars();
+
+  @SkylarkCallable(
+    name = "transitive_exports",
+    structField = true,
+    doc = "Returns transitive set of labels that are being exported from this rule."
+  )
+  public NestedSet<Label> getTransitiveExports();
+
+  @SkylarkCallable(
+    name = "annotation_processing",
+    structField = true,
+    allowReturnNones = true,
+    doc = "Returns information about annotation processing for this Java target."
+  )
+  public JavaAnnotationProcessingApi<?> getGenJarsProvider();
+
+  @SkylarkCallable(
+    name = "compilation_info",
+    structField = true,
+    allowReturnNones = true,
+    doc = "Returns compilation information for this Java target."
+  )
+  public JavaCompilationInfoProviderApi<?> getCompilationInfoProvider();
+}
diff --git a/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/JavaToolchainSkylarkApiProviderApi.java b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/JavaToolchainSkylarkApiProviderApi.java
new file mode 100644
index 0000000000..49a8704c28
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/java/JavaToolchainSkylarkApiProviderApi.java
@@ -0,0 +1,45 @@
+// Copyright 2018 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.devtools.build.lib.skylarkbuildapi.java;
+
+import com.google.devtools.build.lib.skylarkbuildapi.FileApi;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
+
+/**
+ * Provides access to information about the Java toolchain rule.
+ * Accessible as a 'java_toolchain' field on a Target struct.
+ */
+@SkylarkModule(
+    name = "JavaToolchainSkylarkApiProvider",
+    doc =
+        "Provides access to information about the Java toolchain rule. "
+            + "Accessible as a 'java_toolchain' field on a Target struct."
+)
+public interface JavaToolchainSkylarkApiProviderApi {
+
+  @SkylarkCallable(name = "source_version", doc = "The java source version.", structField = true)
+  public String getSourceVersion();
+
+  @SkylarkCallable(name = "target_version", doc = "The java target version.", structField = true)
+  public String getTargetVersion();
+
+  @SkylarkCallable(
+      name = "javac_jar",
+      doc = "The javac jar.",
+      structField = true
+  )
+  public FileApi getJavacJar();
+}