Here you can find the source of getDocument()
private static Document getDocument()
//package com.java2s; /*/*from w w w . j a v a2 s . c o m*/ * JBoss, a division of Red Hat * Copyright 2010, Red Hat Middleware, LLC, and individual * contributors as indicated by the @authors tag. See the * copyright.txt in the distribution for a full listing of * individual contributors. * * This is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * This software is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this software; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA, or see the FSF site: http://www.fsf.org. */ import org.w3c.dom.Document; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; public class Main { private static final ThreadLocal<DocumentBuilder> documentBuilder = new ThreadLocal<DocumentBuilder>() { @Override protected DocumentBuilder initialValue() { DocumentBuilderFactory builderFactory = DocumentBuilderFactory .newInstance(); builderFactory.setNamespaceAware(true); try { return builderFactory.newDocumentBuilder(); } catch (ParserConfigurationException e) { throw new RuntimeException( "Couldn't get a DocumentBuilder", e); } } }; private static Document getDocument() { return documentBuilder.get().newDocument(); } }