https://github.com/google/guava/guava: Guava is a suite of core and expanded libraries that include utility classes, google's collections, io classes, and much much more. 
/*
 * Copyright (C) 2013 The Guava 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 com.google.common.util.concurrent;

import com.google.common.annotations.Beta;
import com.google.common.annotations.GwtCompatible;


Static utility methods pertaining to the Runnable interface. 
Since:16.0
/**
 * Static utility methods pertaining to the {@link Runnable} interface.
 *
 * @since 16.0
 */
@Beta
@GwtCompatible
public final class Runnables {

  private static final Runnable EMPTY_RUNNABLE =
      new Runnable() {
        @Override
        public void run() {}
      };

  
Returns a Runnable instance that does nothing when run. 
/** Returns a {@link Runnable} instance that does nothing when run. */
  public static Runnable doNothing() {
    return EMPTY_RUNNABLE;
  }

  private Runnables() {}
}