test/hotspot/jtreg/runtime/LoaderConstraints/common/PreemptingClassLoader.java

rev 49686 : 8199852: Print more information about class loaders in LinkageErrors.
Reviewed-by: dholmes

*** 1,7 ****
  /*
!  * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
--- 1,7 ----
  /*
!  * Copyright (c) 2017, 2018, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
*** 25,42 ****
  import java.io.*;
  
  public class PreemptingClassLoader extends ClassLoader {
  
      private final Set<String> names = new HashSet<>();
  
      public PreemptingClassLoader(String... names) {
          for (String n : names) this.names.add(n);
      }
  
      protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
          if (!names.contains(name)) return super.loadClass(name, resolve);
!         Class<?> result = findLoadedClass(name);
          if (result == null) {
              String filename = name.replace('.', '/') + ".class";
              try (InputStream data = getResourceAsStream(filename)) {
                  if (data == null) throw new ClassNotFoundException();
                  try (ByteArrayOutputStream buffer = new ByteArrayOutputStream()) {
--- 25,54 ----
  import java.io.*;
  
  public class PreemptingClassLoader extends ClassLoader {
  
      private final Set<String> names = new HashSet<>();
+     boolean checkLoaded = true;
  
      public PreemptingClassLoader(String... names) {
          for (String n : names) this.names.add(n);
      }
  
+     public PreemptingClassLoader(String name, String[] names) {
+         super(name, ClassLoader.getSystemClassLoader());
+         for (String n : names) this.names.add(n);
+     }
+ 
+     public PreemptingClassLoader(String name, String[] names, boolean cL) {
+         super(name, ClassLoader.getSystemClassLoader());
+         for (String n : names) this.names.add(n);
+         checkLoaded = cL;
+     }
+ 
      protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
          if (!names.contains(name)) return super.loadClass(name, resolve);
!         Class<?> result = checkLoaded ? findLoadedClass(name) : null;
          if (result == null) {
              String filename = name.replace('.', '/') + ".class";
              try (InputStream data = getResourceAsStream(filename)) {
                  if (data == null) throw new ClassNotFoundException();
                  try (ByteArrayOutputStream buffer = new ByteArrayOutputStream()) {