Force the given class to be loaded fully. : ClassLoader « Reflection « Java






  1. Java
  2. Reflection
  3. ClassLoader

Force the given class to be loaded fully.

   
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.net.URL;
import java.security.CodeSource;
import java.security.ProtectionDomain;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

/*
 * JBoss, Home of Professional Open Source
 * Copyright 2005, JBoss Inc., 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.
 */

public class Main {

  /**
   * Force the given class to be loaded fully.
   * 
   * <p>
   * This method attempts to locate a static method on the given class the
   * attempts to invoke it with dummy arguments in the hope that the virtual
   * machine will prepare the class for the method call and call all of the
   * static class initializers.
   * 
   * @param type
   *          Class to force load.
   * 
   * @throws NullArgumentException
   *           Type is <i>null</i>.
   */
  public static void forceLoad(final Class type) {
    if (type == null)
      System.out.println("Null Argument Exception");

    // don't attempt to force primitives to load
    if (type.isPrimitive())
      return;

    // don't attempt to force java.* classes to load
    String packageName = Classes.getPackageName(type);
    // System.out.println("package name: " + packageName);

    if (packageName.startsWith("java.") || packageName.startsWith("javax.")) {
      return;
    }

    // System.out.println("forcing class to load: " + type);

    try {
      Method methods[] = type.getDeclaredMethods();
      Method method = null;
      for (int i = 0; i < methods.length; i++) {
        int modifiers = methods[i].getModifiers();
        if (Modifier.isStatic(modifiers)) {
          method = methods[i];
          break;
        }
      }

      if (method != null) {
        method.invoke(null, (Object[]) null);
      } else {
        type.newInstance();
      }
    } catch (Exception ignore) {
      ignore.printStackTrace();
    }
  }
}








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