Here you can find the source of create()
public static String create()
//package com.java2s; /*/*from ww w. ja v a 2 s . co m*/ * Copyright ? 2015-2016 * * This file is part of Spoofax for IntelliJ. * * 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. */ import javax.annotation.Nullable; import java.util.concurrent.atomic.AtomicInteger; public class Main { private static final AtomicInteger counter = new AtomicInteger(); /** * Returns a unique identifier. * * @return The created identifier. */ public static String create() { return create(""); } /** * Returns a unique identifier. * * @param prefix The identifier prefix. * @return The created identifier. */ public static String create(@Nullable final String prefix) { final int value = counter.getAndIncrement(); return ((prefix != null) ? prefix : "") + value; } }