content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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 org.apache.beam.sdk.util;
  
  import java.io.IOException;
  import java.io.ObjectStreamException;
  import java.io.Serializable;
  import org.apache.beam.sdk.coders.Coder;
  
  /**
   * A {@link Serializable} {@link ThreadLocal} which discards any "stored" objects. This allows for
   * Kryo to serialize a {@link Coder} as a final field.
   */
  @SuppressWarnings({
    "nullness" // TODO(https://github.com/apache/beam/issues/20497)
  })
  public class EmptyOnDeserializationThreadLocal<T> extends ThreadLocal<T> implements Serializable {
    private void writeObject(java.io.ObjectOutputStream out) throws IOException {}
  
    private void readObject(java.io.ObjectInputStream in)
        throws IOException, ClassNotFoundException {}
  
    private void readObjectNoData() throws ObjectStreamException {}
  }
  