Merge pull request #2825 from pherl/javawarning

Cherry-pick changes from javalite branch to also fix Java warnings in the master branch

java/core/src/main/java/com/google/protobuf/GeneratedMessage.java

@@ -854,6 +854,7 @@ public abstract class GeneratedMessage extends AbstractMessage
 
     /** Check if a singular extension is present. */
     @Override
+    @SuppressWarnings("unchecked")
     public final <Type> boolean hasExtension(final ExtensionLite<MessageType, Type> extensionLite) {
       Extension<MessageType, Type> extension = checkNotLite(extensionLite);
 
@@ -863,6 +864,7 @@ public abstract class GeneratedMessage extends AbstractMessage
 
     /** Get the number of elements in a repeated extension. */
     @Override
+    @SuppressWarnings("unchecked")
     public final <Type> int getExtensionCount(
         final ExtensionLite<MessageType, List<Type>> extensionLite) {
       Extension<MessageType, List<Type>> extension = checkNotLite(extensionLite);
@@ -2555,6 +2557,7 @@ public abstract class GeneratedMessage extends AbstractMessage
       }
 
       @Override
+      @SuppressWarnings("unchecked")
       public Object get(GeneratedMessage message) {
         List result = new ArrayList();
         for (int i = 0; i < getRepeatedCount(message); i++) {
@@ -2564,6 +2567,7 @@ public abstract class GeneratedMessage extends AbstractMessage
       }
 
       @Override
+      @SuppressWarnings("unchecked")
       public Object get(Builder builder) {
         List result = new ArrayList();
         for (int i = 0; i < getRepeatedCount(builder); i++) {

java/core/src/main/java/com/google/protobuf/GeneratedMessageLite.java

@@ -220,6 +220,7 @@ public abstract class GeneratedMessageLite<
   }
 
   @Override
+  @SuppressWarnings("unchecked")
   public final BuilderType toBuilder() {
     BuilderType builder = (BuilderType) dynamicMethod(MethodToInvoke.NEW_BUILDER);
     builder.mergeFrom((MessageType) this);
@@ -453,6 +454,7 @@ public abstract class GeneratedMessageLite<
      */
     protected FieldSet<ExtensionDescriptor> extensions = FieldSet.newFieldSet();
 
+    @SuppressWarnings("unchecked")
     protected final void mergeExtensionFields(final MessageType other) {
       if (extensions.isImmutable()) {
         extensions = extensions.clone();

java/core/src/main/java/com/google/protobuf/GeneratedMessageV3.java

@@ -866,6 +866,7 @@ public abstract class GeneratedMessageV3 extends AbstractMessage
 
     /** Check if a singular extension is present. */
     @Override
+    @SuppressWarnings("unchecked")
     public final <Type> boolean hasExtension(final ExtensionLite<MessageType, Type> extensionLite) {
       Extension<MessageType, Type> extension = checkNotLite(extensionLite);
 
@@ -875,6 +876,7 @@ public abstract class GeneratedMessageV3 extends AbstractMessage
 
     /** Get the number of elements in a repeated extension. */
     @Override
+    @SuppressWarnings("unchecked")
     public final <Type> int getExtensionCount(
         final ExtensionLite<MessageType, List<Type>> extensionLite) {
       Extension<MessageType, List<Type>> extension = checkNotLite(extensionLite);
@@ -2219,6 +2221,7 @@ public abstract class GeneratedMessageV3 extends AbstractMessage
       }
 
       @Override
+      @SuppressWarnings("unchecked")
       public Object get(GeneratedMessageV3 message) {
         List result = new ArrayList();
         for (int i = 0; i < getRepeatedCount(message); i++) {
@@ -2228,6 +2231,7 @@ public abstract class GeneratedMessageV3 extends AbstractMessage
       }
 
       @Override
+      @SuppressWarnings("unchecked")
       public Object get(Builder builder) {
         List result = new ArrayList();
         for (int i = 0; i < getRepeatedCount(builder); i++) {

java/core/src/main/java/com/google/protobuf/MapEntry.java

@@ -89,6 +89,7 @@ public final class MapEntry<K, V> extends AbstractMessage {
   }
 
   /** Create a MapEntry with the provided key and value. */
+  @SuppressWarnings("unchecked")
   private MapEntry(Metadata metadata, K key, V value) {
     this.key = key;
     this.value = value;
@@ -435,6 +436,7 @@ public final class MapEntry<K, V> extends AbstractMessage {
     }
 
     @Override
+    @SuppressWarnings("unchecked")
     public Builder<K, V> clone() {
       return new Builder(metadata, key, value);
     }

java/core/src/main/java/com/google/protobuf/MapField.java

@@ -100,6 +100,7 @@ public class MapField<K, V> implements MutabilityOracle {
     }
 
     @Override
+    @SuppressWarnings("unchecked")
     public void convertMessageToKeyAndValue(Message message, Map<K, V> map) {
       MapEntry<K, V> entry = (MapEntry<K, V>) message;
       map.put(entry.getKey(), entry.getValue());

src/google/protobuf/compiler/java/java_message.cc

@@ -1453,6 +1453,7 @@ void ImmutableMessageGenerator::GenerateAnyMethods(io::Printer* printer) {
     "\n"
     "private volatile com.google.protobuf.Message cachedUnpackValue;\n"
     "\n"
+    "@java.lang.SuppressWarnings(\"unchecked\")\n"
     "public <T extends com.google.protobuf.Message> T unpack(\n"
     "    java.lang.Class<T> clazz)\n"
     "    throws com.google.protobuf.InvalidProtocolBufferException {\n"

src/google/protobuf/compiler/java/java_message_lite.cc

@@ -345,6 +345,7 @@ void ImmutableMessageLiteGenerator::Generate(io::Printer* printer) {
   }
 
   printer->Print(
+    "@java.lang.SuppressWarnings(\"unchecked\")\n"
     "protected final Object dynamicMethod(\n"
     "    com.google.protobuf.GeneratedMessageLite.MethodToInvoke method,\n"
     "    Object arg0, Object arg1) {\n"