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1   package org.codehaus.plexus.compiler.javac;
2   
3   /**
4    * The MIT License
5    *
6    * Copyright (c) 2005, The Codehaus
7    *
8    * Permission is hereby granted, free of charge, to any person obtaining a copy of
9    * this software and associated documentation files (the "Software"), to deal in
10   * the Software without restriction, including without limitation the rights to
11   * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
12   * of the Software, and to permit persons to whom the Software is furnished to do
13   * so, subject to the following conditions:
14   *
15   * The above copyright notice and this permission notice shall be included in all
16   * copies or substantial portions of the Software.
17   *
18   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
21   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
23   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
24   * SOFTWARE.
25   */
26  
27  import java.net.URLClassLoader;
28  import java.net.URL;
29  
30  public class IsolatedClassLoader
31      extends URLClassLoader
32  {
33      private ClassLoader parentClassLoader = ClassLoader.getSystemClassLoader();
34  
35      public IsolatedClassLoader()
36      {
37          super( new URL[0], null );
38      }
39  
40      public void addURL( URL url )
41      {
42          super.addURL( url );
43      }
44  
45      public synchronized Class<?> loadClass( String className )
46          throws ClassNotFoundException
47      {
48          Class<?> c = findLoadedClass( className );
49  
50          ClassNotFoundException ex = null;
51  
52          if ( c == null )
53          {
54              try
55              {
56                  c = findClass( className );
57              }
58              catch ( ClassNotFoundException e )
59              {
60                  ex = e;
61  
62                  if ( parentClassLoader != null )
63                  {
64                      c = parentClassLoader.loadClass( className );
65                  }
66              }
67          }
68  
69          if ( c == null )
70          {
71              throw ex;
72          }
73  
74          return c;
75      }
76  }