Re-arrange JavaBuilder output jar handling

To make it more obvious that the JarOutputStream is closed (see #2538).

--
PiperOrigin-RevId: 148791125
MOS_MIGRATED_REVID=148791125

3 files changed, 48 insertions, 44 deletions

diff --git a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/SimpleJavaLibraryBuilder.java b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/SimpleJavaLibraryBuilder.java
index eb03a9bae7..68b0f1015b 100644
--- a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/SimpleJavaLibraryBuilder.java
+++ b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/SimpleJavaLibraryBuilder.java
@@ -139,10 +139,13 @@ public class SimpleJavaLibraryBuilder implements Closeable {
 
   public void buildGensrcJar(JavaLibraryBuildRequest build) throws IOException {
     JarCreator jar = new JarCreator(build.getGeneratedSourcesOutputJar());
-    jar.setNormalize(true);
-    jar.setCompression(build.compressJar());
-    jar.addDirectory(build.getSourceGenDir());
-    jar.execute();
+    try {
+      jar.setNormalize(true);
+      jar.setCompression(build.compressJar());
+      jar.addDirectory(build.getSourceGenDir());
+    } finally {
+      jar.execute();
+    }
   }
 
   /**
@@ -193,41 +196,43 @@ public class SimpleJavaLibraryBuilder implements Closeable {
 
   public void buildJar(JavaLibraryBuildRequest build) throws IOException {
     JarCreator jar = new JarCreator(build.getOutputJar());
-    jar.setNormalize(true);
-    jar.setCompression(build.compressJar());
+    try {
+      jar.setNormalize(true);
+      jar.setCompression(build.compressJar());
 
-    for (String resourceJar : build.getResourceJars()) {
-      for (Path root : getJarFileSystem(Paths.get(resourceJar)).getRootDirectories()) {
-        Files.walkFileTree(
-            root,
-            new SimpleFileVisitor<Path>() {
-              @Override
-              public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs)
-                  throws IOException {
-                // TODO(b/28452451): omit directories entries from jar files
-                if (dir.getNameCount() > 0) {
-                  jar.addEntry(root.relativize(dir).toString(), dir);
+      for (String resourceJar : build.getResourceJars()) {
+        for (Path root : getJarFileSystem(Paths.get(resourceJar)).getRootDirectories()) {
+          Files.walkFileTree(
+              root,
+              new SimpleFileVisitor<Path>() {
+                @Override
+                public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs)
+                    throws IOException {
+                  // TODO(b/28452451): omit directories entries from jar files
+                  if (dir.getNameCount() > 0) {
+                    jar.addEntry(root.relativize(dir).toString(), dir);
+                  }
+                  return FileVisitResult.CONTINUE;
                 }
-                return FileVisitResult.CONTINUE;
-              }
 
-              @Override
-              public FileVisitResult visitFile(Path path, BasicFileAttributes attrs)
-                  throws IOException {
-                jar.addEntry(root.relativize(path).toString(), path);
-                return FileVisitResult.CONTINUE;
-              }
-            });
+                @Override
+                public FileVisitResult visitFile(Path path, BasicFileAttributes attrs)
+                    throws IOException {
+                  jar.addEntry(root.relativize(path).toString(), path);
+                  return FileVisitResult.CONTINUE;
+                }
+              });
+        }
       }
-    }
-
-    jar.addDirectory(build.getClassDir());
 
-    jar.addRootEntries(build.getRootResourceFiles());
-    addResourceEntries(jar, build.getResourceFiles());
-    addMessageEntries(jar, build.getMessageFiles());
+      jar.addDirectory(build.getClassDir());
 
-    jar.execute();
+      jar.addRootEntries(build.getRootResourceFiles());
+      addResourceEntries(jar, build.getResourceFiles());
+      addMessageEntries(jar, build.getMessageFiles());
+    } finally {
+      jar.execute();
+    }
   }
 
   /**
diff --git a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/jarhelper/JarCreator.java b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/jarhelper/JarCreator.java
index c3a5d84182..46232bc879 100644
--- a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/jarhelper/JarCreator.java
+++ b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/jarhelper/JarCreator.java
@@ -20,6 +20,7 @@ import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
+import java.io.OutputStream;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.Collection;
@@ -173,17 +174,16 @@ public class JarCreator extends JarHelper {
    * @throws IOException if the Jar cannot be written or any of the entries cannot be read.
    */
   public void execute() throws IOException {
-    out = new JarOutputStream(new BufferedOutputStream(new FileOutputStream(jarFile)));
+    try (OutputStream os = new FileOutputStream(jarFile);
+        BufferedOutputStream bos = new BufferedOutputStream(os);
+        JarOutputStream out = new JarOutputStream(bos)) {
+
+      // Create the manifest entry in the Jar file
+      writeManifestEntry(out, manifestContent());
 
-    // Create the manifest entry in the Jar file
-    writeManifestEntry(manifestContent());
-    try {
       for (Map.Entry<String, Path> entry : jarEntries.entrySet()) {
-        copyEntry(entry.getKey(), entry.getValue());
+        copyEntry(out, entry.getKey(), entry.getValue());
       }
-    } finally {
-      out.closeEntry();
-      out.close();
     }
   }
 
diff --git a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/jarhelper/JarHelper.java b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/jarhelper/JarHelper.java
index 5e7d0227ea..ff4b8e055f 100644
--- a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/jarhelper/JarHelper.java
+++ b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/jarhelper/JarHelper.java
@@ -54,7 +54,6 @@ public class JarHelper {
 
   // The state needed to create the Jar
   protected final Set<String> names = new HashSet<>();
-  protected JarOutputStream out;
 
   public JarHelper(String filename) {
     jarFile = filename;
@@ -152,7 +151,7 @@ public class JarHelper {
    * @param content the Manifest content to write to the manifest entry.
    * @throws IOException
    */
-  protected void writeManifestEntry(byte[] content) throws IOException {
+  protected void writeManifestEntry(JarOutputStream out, byte[] content) throws IOException {
     int oldStorageMethod = storageMethod;
     // Do not compress small manifest files, the compressed one is frequently
     // larger than the original. The threshold of 256 bytes is somewhat arbitrary.
@@ -171,7 +170,7 @@ public class JarHelper {
    * Copies file or directory entries from the file system into the jar. Directory entries will be
    * detected and their names automatically '/' suffixed.
    */
-  protected void copyEntry(String name, Path path) throws IOException {
+  protected void copyEntry(JarOutputStream out, String name, Path path) throws IOException {
     if (!names.contains(name)) {
       if (!Files.exists(path)) {
         throw new FileNotFoundException(path.toAbsolutePath() + " (No such file or directory)");