1 /*
   2  * Copyright (c) 2013, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package jdk.testlibrary.jfr;
  27 
  28 import java.io.DataInputStream;
  29 import java.io.IOException;
  30 import java.io.InputStream;
  31 
  32 /**
  33  * Custom class loader which will try to load the class via getResourceAsStream().
  34  * If there are any errors, the parent class loader will be used instead.
  35  */
  36 public class TestClassLoader extends ClassLoader {
  37     static public final String CLASS_LOADER_NAME = "JFR TestClassLoader";
  38 
  39     public TestClassLoader() {
  40         // super(CLASS_LOADER_NAME, ClassLoader.getSystemClassLoader());
  41         super(ClassLoader.getSystemClassLoader());
  42     }
  43 
  44     public Class<?> loadClass(String name) throws ClassNotFoundException {
  45 
  46         InputStream is = null;
  47         DataInputStream dis = null;
  48         try {
  49             String resourceName = name.replace('.', '/') + ".class";
  50             is = getResourceAsStream(resourceName);
  51             if (is != null) {
  52                 int i = is.available();
  53                 byte buf[] = new byte[i];
  54                 dis = new DataInputStream(is);
  55                 dis.readFully(buf);
  56                 dis.close();
  57                 return defineClass(name, buf, 0, buf.length);
  58             }
  59         } catch (SecurityException e) {
  60             // This error will happen quite often (for example when loading
  61             // "java.lang...").
  62             // Ignore this error and use parent class loader.
  63         } catch (IOException e) {
  64             // Unexpected error. Use parent class loader.
  65             e.printStackTrace();
  66         } finally {
  67             if (dis != null) {
  68                 try {
  69                     dis.close();
  70                 } catch (IOException e) {
  71                     e.printStackTrace();
  72                 }
  73             }
  74         }
  75         return super.loadClass(name);
  76     }
  77 
  78 }