header + class javadoc

api/src/main/java/io/grpc/InternalStatusRuntimeException.java

@@ -1,7 +1,30 @@
+/*
+ * Copyright 2015 The gRPC Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package io.grpc;
 
 import javax.annotation.Nullable;
 
+/**
+ * StatusRuntimeException without stack trace, implemented as a subclass, as the
+ * {@code String, Throwable, boolean, boolean} constructor is not available in supported version
+ * of Android.
+ *
+ * @see StatusRuntimeException
+ */
 class InternalStatusRuntimeException extends StatusRuntimeException {
   private static final long serialVersionUID = 5225396310618305864L;