7059170: Assume availablility of URLClassLoader.close

Reviewed-by: jjg

src/share/classes/com/sun/tools/javac/util/BaseFileManager.java

 /*
- * Copyright (c) 2009, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2009, 2013, 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
@@ -112,9 +112,8 @@ public abstract class BaseFileManager {
     protected ClassLoader getClassLoader(URL[] urls) {
         ClassLoader thisClassLoader = getClass().getClassLoader();
 
-        // Bug: 6558476
-        // Ideally, ClassLoader should be Closeable, but before JDK7 it is not.
-        // On older versions, try the following, to get a closeable classloader.
+        // Allow the following to specify a closeable classloader
+        // other than URLClassLoader.
 
         // 1: Allow client to specify the class to use via hidden option
         if (classLoaderClass != null) {
@@ -128,19 +127,6 @@ public abstract class BaseFileManager {
                 // ignore errors loading user-provided class loader, fall through
             }
         }
-
-        // 2: If URLClassLoader implements Closeable, use that.
-        if (Closeable.class.isAssignableFrom(URLClassLoader.class))
-            return new URLClassLoader(urls, thisClassLoader);
-
-        // 3: Try using private reflection-based CloseableURLClassLoader
-        try {
-            return new CloseableURLClassLoader(urls, thisClassLoader);
-        } catch (Throwable t) {
-            // ignore errors loading workaround class loader, fall through
-        }
-
-        // 4: If all else fails, use plain old standard URLClassLoader
         return new URLClassLoader(urls, thisClassLoader);
     }
 

src/share/classes/com/sun/tools/javac/util/CloseableURLClassLoader.java

-/*
- * Copyright (c) 2007, 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.  Oracle designates this
- * particular file as subject to the "Classpath" exception as provided
- * by Oracle in the LICENSE file that accompanied this code.
- *
- * This code 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 General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-package com.sun.tools.javac.util;
-
-import java.io.Closeable;
-import java.io.IOException;
-import java.lang.reflect.Field;
-import java.net.URL;
-import java.net.URLClassLoader;
-import java.util.ArrayList;
-import java.util.jar.JarFile;
-
-/**
- * A URLClassLoader that also implements Closeable.
- * Reflection is used to access internal data structures in the URLClassLoader,
- * since no public API exists for this purpose. Therefore this code is somewhat
- * fragile. Caveat emptor.
- * @throws Error if the internal data structures are not as expected.
- *
- *  <p><b>This is NOT part of any supported API.
- *  If you write code that depends on this, you do so at your own risk.
- *  This code and its internal interfaces are subject to change or
- *  deletion without notice.</b>
- */
-public class CloseableURLClassLoader
-        extends URLClassLoader implements Closeable {
-    public CloseableURLClassLoader(URL[] urls, ClassLoader parent) throws Error {
-        super(urls, parent);
-        try {
-            getLoaders(); //proactive check that URLClassLoader is as expected
-        } catch (Throwable t) {
-            throw new Error("cannot create CloseableURLClassLoader", t);
-        }
-    }
-
-    /**
-     * Close any jar files that may have been opened by the class loader.
-     * Reflection is used to access the jar files in the URLClassLoader's
-     * internal data structures.
-     * @throws java.io.IOException if the jar files cannot be found for any
-     * reson, or if closing the jar file itself causes an IOException.
-     */
-    @Override
-    public void close() throws IOException {
-        try {
-            for (Object l: getLoaders()) {
-                if (l.getClass().getName().equals("sun.misc.URLClassPath$JarLoader")) {
-                    Field jarField = l.getClass().getDeclaredField("jar");
-                    JarFile jar = (JarFile) getField(l, jarField);
-                    if (jar != null) {
-                        //System.err.println("CloseableURLClassLoader: closing " + jar);
-                        jar.close();
-                    }
-                }
-            }
-        } catch (Throwable t) {
-            IOException e = new IOException("cannot close class loader");
-            e.initCause(t);
-            throw e;
-        }
-    }
-
-    private ArrayList<?> getLoaders()
-            throws NoSuchFieldException, IllegalArgumentException, IllegalAccessException
-    {
-        Field ucpField = URLClassLoader.class.getDeclaredField("ucp");
-        Object urlClassPath = getField(this, ucpField);
-        if (urlClassPath == null)
-            throw new AssertionError("urlClassPath not set in URLClassLoader");
-        Field loadersField = urlClassPath.getClass().getDeclaredField("loaders");
-        return (ArrayList<?>) getField(urlClassPath, loadersField);
-    }
-
-    private Object getField(Object o, Field f)
-            throws IllegalArgumentException, IllegalAccessException {
-        boolean prev = f.isAccessible();
-        try {
-            f.setAccessible(true);
-            return f.get(o);
-        } finally {
-            f.setAccessible(prev);
-        }
-    }
-
-}