Load class : AccessController « Security « Java

1. Java
2. Security
3. AccessController

Load class

 

/*
 * Copyright  2003-2008 The Apache Software Foundation.
 *
 *  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 java.lang.reflect.InvocationTargetException;
import java.security.AccessController;
import java.security.PrivilegedAction;

public class Main {

  /**
   * If running under JDK 1.2 load the specified class using the
   * <code>Thread</code> <code>contextClassLoader</code> if that
   * fails try Class.forname.
   * <p/>
   *
   * @param clazz
   * @return TODO
   * @throws ClassNotFoundException
   */
  public static Class loadClass(String clazz) throws ClassNotFoundException {
      return loadClass(clazz, true);
  }
  
  public static Class loadClass(String clazz, boolean warn) throws ClassNotFoundException {
      try {
          ClassLoader tcl = getTCL(); 
          
          if (tcl != null) {
              Class c = tcl.loadClass(clazz);
              if (c != null) {
                  return c;
              }
          }
      } catch (Throwable e) {
      }
      // we reached here because tcl was null or because of a
      // security exception, or because clazz could not be loaded...
      // In any case we now try one more time
      return Class.forName(clazz);
  }
  /**
   * Get the Thread context class loader.
   * <p/>
   *
   * @return the Thread context class loader
   * @throws IllegalAccessException
   * @throws InvocationTargetException
   */
  public static ClassLoader getTCL() throws IllegalAccessException, InvocationTargetException {
       return (ClassLoader)AccessController.doPrivileged(new PrivilegedAction() {
          public Object run() {
              return Thread.currentThread().getContextClassLoader();
          }
       });
  }
}

   
  

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