1 files changed, 40 insertions, 19 deletions

diff --git a/java/core/src/main/java/com/google/protobuf/GeneratedMessageLite.java b/java/core/src/main/java/com/google/protobuf/GeneratedMessageLite.java
index 7116ae1c..99864964 100644
--- a/java/core/src/main/java/com/google/protobuf/GeneratedMessageLite.java
+++ b/java/core/src/main/java/com/google/protobuf/GeneratedMessageLite.java
@@ -220,7 +220,7 @@ public abstract class GeneratedMessageLite<
 
   @Override
   public final boolean isInitialized() {
-    return dynamicMethod(MethodToInvoke.IS_INITIALIZED, Boolean.TRUE) != null;
+    return isInitialized((MessageType) this, Boolean.TRUE);
   }
 
   @Override
@@ -240,6 +240,8 @@ public abstract class GeneratedMessageLite<
   public static enum MethodToInvoke {
     // Rely on/modify instance state
     IS_INITIALIZED,
+    GET_MEMOIZED_IS_INITIALIZED,
+    SET_MEMOIZED_IS_INITIALIZED,
     VISIT,
     MERGE_FROM_STREAM,
     MAKE_IMMUTABLE,
@@ -256,25 +258,30 @@ public abstract class GeneratedMessageLite<
    * Theses different kinds of operations are required to implement message-level operations for
    * builders in the runtime. This method bundles those operations to reduce the generated methods
    * count.
+   *
    * <ul>
-   * <li>{@code MERGE_FROM_STREAM} is parameterized with an {@link CodedInputStream} and
-   * {@link ExtensionRegistryLite}. It consumes the input stream, parsing the contents into the
-   * returned protocol buffer. If parsing throws an {@link InvalidProtocolBufferException}, the
-   * implementation wraps it in a RuntimeException.
-   * <li>{@code NEW_INSTANCE} returns a new instance of the protocol buffer that has not yet been
-   * made immutable. See {@code MAKE_IMMUTABLE}.
-   * <li>{@code IS_INITIALIZED} is parameterized with a {@code Boolean} detailing whether to
-   * memoize. It returns {@code null} for false and the default instance for true. We optionally
-   * memoize to support the Builder case, where memoization is not desired.
-   * <li>{@code NEW_BUILDER} returns a {@code BuilderType} instance.
-   * <li>{@code VISIT} is parameterized with a {@code Visitor} and a {@code MessageType} and
-   * recursively iterates through the fields side by side between this and the instance.
-   * <li>{@code MAKE_IMMUTABLE} sets all internal fields to an immutable state.
+   *   <li>{@code MERGE_FROM_STREAM} is parameterized with an {@link CodedInputStream} and {@link
+   *       ExtensionRegistryLite}. It consumes the input stream, parsing the contents into the
+   *       returned protocol buffer. If parsing throws an {@link InvalidProtocolBufferException},
+   *       the implementation wraps it in a RuntimeException.
+   *   <li>{@code NEW_INSTANCE} returns a new instance of the protocol buffer that has not yet been
+   *       made immutable. See {@code MAKE_IMMUTABLE}.
+   *   <li>{@code IS_INITIALIZED} returns {@code null} for false and the default instance for true.
+   *       It doesn't use or modify any memoized value.
+   *   <li>{@code GET_MEMOIZED_IS_INITIALIZED} returns the memoized {@code isInitialized} byte
+   *       value.
+   *   <li>{@code SET_MEMOIZED_IS_INITIALIZED} sets the memoized {@code isInitilaized} byte value to
+   *       1 if the first parameter is not null, or to 0 if the first parameter is null.
+   *   <li>{@code NEW_BUILDER} returns a {@code BuilderType} instance.
+   *   <li>{@code VISIT} is parameterized with a {@code Visitor} and a {@code MessageType} and
+   *       recursively iterates through the fields side by side between this and the instance.
+   *   <li>{@code MAKE_IMMUTABLE} sets all internal fields to an immutable state.
    * </ul>
+   *
    * This method, plus the implementation of the Builder, enables the Builder class to be proguarded
    * away entirely on Android.
-   * <p>
-   * For use by generated code only.
+   *
+   * <p>For use by generated code only.
    */
   protected abstract Object dynamicMethod(MethodToInvoke method, Object arg0, Object arg1);
 
@@ -297,9 +304,9 @@ public abstract class GeneratedMessageLite<
     unknownFields = visitor.visitUnknownFields(unknownFields, other.unknownFields);
   }
 
+
   /**
-   * Merge some unknown fields into the {@link UnknownFieldSetLite} for this
-   * message.
+   * Merge some unknown fields into the {@link UnknownFieldSetLite} for this message.
    *
    * <p>For use by generated code only.
    */
@@ -1403,7 +1410,21 @@ public abstract class GeneratedMessageLite<
    */
   protected static final <T extends GeneratedMessageLite<T, ?>> boolean isInitialized(
       T message, boolean shouldMemoize) {
-    return message.dynamicMethod(MethodToInvoke.IS_INITIALIZED, shouldMemoize) != null;
+    byte memoizedIsInitialized =
+        (Byte) message.dynamicMethod(MethodToInvoke.GET_MEMOIZED_IS_INITIALIZED);
+    if (memoizedIsInitialized == 1) {
+      return true;
+    }
+    if (memoizedIsInitialized == 0) {
+      return false;
+    }
+    boolean isInitialized =
+        message.dynamicMethod(MethodToInvoke.IS_INITIALIZED, Boolean.FALSE) != null;
+    if (shouldMemoize) {
+      message.dynamicMethod(
+          MethodToInvoke.SET_MEMOIZED_IS_INITIALIZED, isInitialized ? message : null);
+    }
+    return isInitialized;
   }
 
   protected static final <T extends GeneratedMessageLite<T, ?>> void makeImmutable(T message) {