Remove unnecessary cast in generated Java code

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

@@ -461,35 +461,35 @@ GenerateCommonBuilderMethods(io::Printer* printer) {
   printer->Print(
     "@java.lang.Override\n"
     "public Builder clone() {\n"
-    "  return (Builder) super.clone();\n"
+    "  return super.clone();\n"
     "}\n"
     "@java.lang.Override\n"
     "public Builder setField(\n"
     "    com.google.protobuf.Descriptors.FieldDescriptor field,\n"
     "    java.lang.Object value) {\n"
-    "  return (Builder) super.setField(field, value);\n"
+    "  return super.setField(field, value);\n"
     "}\n"
     "@java.lang.Override\n"
     "public Builder clearField(\n"
     "    com.google.protobuf.Descriptors.FieldDescriptor field) {\n"
-    "  return (Builder) super.clearField(field);\n"
+    "  return super.clearField(field);\n"
     "}\n"
     "@java.lang.Override\n"
     "public Builder clearOneof(\n"
     "    com.google.protobuf.Descriptors.OneofDescriptor oneof) {\n"
-    "  return (Builder) super.clearOneof(oneof);\n"
+    "  return super.clearOneof(oneof);\n"
     "}\n"
     "@java.lang.Override\n"
     "public Builder setRepeatedField(\n"
     "    com.google.protobuf.Descriptors.FieldDescriptor field,\n"
     "    int index, java.lang.Object value) {\n"
-    "  return (Builder) super.setRepeatedField(field, index, value);\n"
+    "  return super.setRepeatedField(field, index, value);\n"
     "}\n"
     "@java.lang.Override\n"
     "public Builder addRepeatedField(\n"
     "    com.google.protobuf.Descriptors.FieldDescriptor field,\n"
     "    java.lang.Object value) {\n"
-    "  return (Builder) super.addRepeatedField(field, value);\n"
+    "  return super.addRepeatedField(field, value);\n"
     "}\n");
 
   if (descriptor_->extension_range_count() > 0) {
@@ -499,27 +499,27 @@ GenerateCommonBuilderMethods(io::Printer* printer) {
       "    com.google.protobuf.GeneratedMessage.GeneratedExtension<\n"
       "        $classname$, Type> extension,\n"
       "    Type value) {\n"
-      "  return (Builder) super.setExtension(extension, value);\n"
+      "  return super.setExtension(extension, value);\n"
       "}\n"
       "@java.lang.Override\n"
       "public <Type> Builder setExtension(\n"
       "    com.google.protobuf.GeneratedMessage.GeneratedExtension<\n"
       "        $classname$, java.util.List<Type>> extension,\n"
       "    int index, Type value) {\n"
-      "  return (Builder) super.setExtension(extension, index, value);\n"
+      "  return super.setExtension(extension, index, value);\n"
       "}\n"
       "@java.lang.Override\n"
       "public <Type> Builder addExtension(\n"
       "    com.google.protobuf.GeneratedMessage.GeneratedExtension<\n"
       "        $classname$, java.util.List<Type>> extension,\n"
       "    Type value) {\n"
-      "  return (Builder) super.addExtension(extension, value);\n"
+      "  return super.addExtension(extension, value);\n"
       "}\n"
       "@java.lang.Override\n"
       "public <Type> Builder clearExtension(\n"
       "    com.google.protobuf.GeneratedMessage.GeneratedExtension<\n"
       "        $classname$, ?> extension) {\n"
-      "  return (Builder) super.clearExtension(extension);\n"
+      "  return super.clearExtension(extension);\n"
       "}\n",
       "classname", name_resolver_->GetImmutableClassName(descriptor_));
   }