diff --git a/src/google/protobuf/compiler/java/helpers.h b/src/google/protobuf/compiler/java/helpers.h
index 52b4017cf562..d99e085a650c 100644
--- a/src/google/protobuf/compiler/java/helpers.h
+++ b/src/google/protobuf/compiler/java/helpers.h
@@ -78,8 +78,7 @@ std::string UniqueFileScopeIdentifier(const Descriptor* descriptor);
 // Gets the unqualified class name for the file.  For each .proto file, there
 // will be one Java class containing all the immutable messages and another
 // Java class containing all the mutable messages.
-// TODO: remove the default value after updating client code.
-std::string FileClassName(const FileDescriptor* file, bool immutable = true);
+std::string FileClassName(const FileDescriptor* file, bool immutable);
 
 // Returns the file's Java package name.
 std::string FileJavaPackage(const FileDescriptor* file, bool immutable,
diff --git a/src/google/protobuf/compiler/java/names.cc b/src/google/protobuf/compiler/java/names.cc
index ae18ee2e4ee9..7f026ecaf6d2 100644
--- a/src/google/protobuf/compiler/java/names.cc
+++ b/src/google/protobuf/compiler/java/names.cc
@@ -141,6 +141,14 @@ std::string FileJavaPackage(const FileDescriptor* file, Options options) {
   return FileJavaPackage(file, true /* immutable */, options);
 }
 
+std::string JavaPackageDirectory(const FileDescriptor* file) {
+  return JavaPackageToDir(FileJavaPackage(file));
+}
+
+std::string FileClassName(const FileDescriptor* file) {
+  return FileClassName(file, /*immutable=*/true);
+}
+
 std::string CapitalizedFieldName(const FieldDescriptor* field) {
   return UnderscoresToCamelCase(FieldName(field), true);
 }
diff --git a/src/google/protobuf/compiler/java/names.h b/src/google/protobuf/compiler/java/names.h
index d6402fc5d365..c2eb34cb3765 100644
--- a/src/google/protobuf/compiler/java/names.h
+++ b/src/google/protobuf/compiler/java/names.h
@@ -72,6 +72,20 @@ std::string ClassName(const ServiceDescriptor* descriptor);
 std::string FileJavaPackage(const FileDescriptor* descriptor,
                             Options options = {});
 
+// Requires:
+//   descriptor != NULL
+//
+// Returns:
+//   Java package directory.
+std::string JavaPackageDirectory(const FileDescriptor* file);
+
+// Requires:
+//   descriptor != NULL
+//
+// Returns:
+//   The unqualified Java class name.
+std::string FileClassName(const FileDescriptor* file);
+
 // Requires:
 //   descriptor != NULL
 // Returns: