[VFS-424] VFS 2.0 class loading breaks in OSGi, regression from 1.0

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0
• Fix Version/s: 2.1

Environment

Apache Maven 3.0.4 (r1232337; 2012-01-17 03:44:56-0500)
Maven home: C:\Java\apache-maven-3.0.4\bin\..
Java version: 1.6.0_31, vendor: Sun Microsystems Inc.
Java home: C:\Program Files\Java\jdk1.6.0_31\jre
Default locale: en_US, platform encoding: Cp1252
OS name: "windows 7", version: "6.1", arch: "amd64", family: "windows"

• Assignee: Bernd Eckenfels
• Reporter: Gary D. Gregory
• Created: 22/Jun/12 01:24
• Updated: 11/Aug/16 17:24
• Resolved: 02/Oct/15 15:14

Description

Class loading changed between version 1.0 and 2.0 in org.apache.commons.vfs2.impl.StandardFileSystemManager.init()

This breaks our app server running under OSGi (Equinox) like this:

org.apache.commons.vfs2.FileSystemException: Could not create a file system manager of class "org.apache.commons.vfs2.impl.StandardFileSystemManager".
    at org.apache.commons.vfs2.VFS.createManager(VFS.java:99)
    at org.apache.commons.vfs2.VFS.getManager(VFS.java:50)
    at com.seagullsw.toolbox.config.ConfigurationDirectory.resolveFileObject(ConfigurationDirectory.java:315)
    at com.seagullsw.toolbox.config.Configuration.resolveFileObject(Configuration.java:135)
<Snip: ...my app frames...>
    at com.seagullsw.appinterface.server.osgi.JCicsOsgiTestCase.testJcicsOsgiRoundtrip(JCicsOsgiTestCase.java:226)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.junit.internal.runners.TestMethod.invoke(TestMethod.java:66)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.runTestMethod(PowerMockJUnit44RunnerDelegateImpl.java:307)
    at org.junit.internal.runners.MethodRoadie$2.run(MethodRoadie.java:86)
    at org.junit.internal.runners.MethodRoadie.runBeforesThenTestThenAfters(MethodRoadie.java:94)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.executeTest(PowerMockJUnit44RunnerDelegateImpl.java:294)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.executeTestInSuper(PowerMockJUnit47RunnerDelegateImpl.java:112)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.executeTest(PowerMockJUnit47RunnerDelegateImpl.java:73)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.runBeforesThenTestThenAfters(PowerMockJUnit44RunnerDelegateImpl.java:282)
    at org.junit.internal.runners.MethodRoadie.runTest(MethodRoadie.java:84)
    at org.junit.internal.runners.MethodRoadie.run(MethodRoadie.java:49)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.invokeTestMethod(PowerMockJUnit44RunnerDelegateImpl.java:207)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.runMethods(PowerMockJUnit44RunnerDelegateImpl.java:146)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$1.run(PowerMockJUnit44RunnerDelegateImpl.java:120)
    at org.junit.internal.runners.ClassRoadie.runUnprotected(ClassRoadie.java:34)
    at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:44)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.run(PowerMockJUnit44RunnerDelegateImpl.java:118)
    at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.run(JUnit4TestSuiteChunkerImpl.java:102)
    at org.powermock.modules.junit4.common.internal.impl.AbstractCommonPowerMockRunner.run(AbstractCommonPowerMockRunner.java:53)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: org.apache.commons.vfs2.FileSystemException: Could not load VFS configuration from "bundleresource://7.fwk545215872:34/org/apache/commons/vfs2/impl/providers.xml".
    at org.apache.commons.vfs2.impl.StandardFileSystemManager.configure(StandardFileSystemManager.java:199)
    at org.apache.commons.vfs2.impl.StandardFileSystemManager.init(StandardFileSystemManager.java:123)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.apache.commons.vfs2.VFS.createManager(VFS.java:88)
    ... 49 more
Caused by: java.lang.ClassCastException: org.apache.commons.vfs2.provider.local.DefaultLocalFileProvider cannot be cast to org.apache.commons.vfs2.provider.FileProvider
    at org.apache.commons.vfs2.impl.StandardFileSystemManager.addProvider(StandardFileSystemManager.java:371)
    at org.apache.commons.vfs2.impl.StandardFileSystemManager.configure(StandardFileSystemManager.java:270)
    at org.apache.commons.vfs2.impl.StandardFileSystemManager.configure(StandardFileSystemManager.java:195)
    ... 55 more

Which I work around with this hack:

    private void initVfs() {
        StandardFileSystemManager fsm = new StandardFileSystemManager();
        fsm.setClassLoader(fsm.getClass().getClassLoader());
        try {
            FieldUtils.writeDeclaredStaticField(VFS.class, "instance", fsm, true);
            fsm.init();
        } catch (FileSystemException e) {
            ...
        } catch (IllegalAccessException e) {
            ...
        }
    }

Two questions:

(1) Why is org.apache.commons.vfs2.VFS.getManager() coded with a class name ref instead of the a real Class object or an actual instance:

    public static synchronized FileSystemManager getManager()
        throws FileSystemException
    {
        if (instance == null)
        {
            instance = createManager("org.apache.commons.vfs2.impl.StandardFileSystemManager");
        }
        return instance;
    }

Why not:

    public static synchronized FileSystemManager getManager()
        throws FileSystemException
    {
        if (instance == null)
        {
            instance = new StandardFileSystemManager();
            // where the StandardFileSystemManager constructor calls init();
        }
        return instance;
    }

If not, what about adding a setManager(FileSystemManager)?

This did not happen in 1.0, it worked fine in OSGi.

In 1.0, the init() method is:

    public void init() throws FileSystemException
    {
        // Set the replicator and temporary file store (use the same component)
        final DefaultFileReplicator replicator = createDefaultFileReplicator();
        setReplicator(new PrivilegedFileReplicator(replicator));
        setTemporaryFileStore(replicator);

        if (classLoader == null)
        {
            // Use default classloader
            classLoader = getClass().getClassLoader();
        }
        if (configUri == null)
        {
            // Use default config
            final URL url = getClass().getResource(CONFIG_RESOURCE);
            if (url == null)
            {
                throw new FileSystemException("vfs.impl/find-config-file.error", CONFIG_RESOURCE);
            }
            configUri = url;
        }

        // Configure
        configure(configUri);

        // Configure Plugins
        configurePlugins();

        // Initialise super-class
        super.init();
    }

In 2.0, the init() method is:

    public void init() throws FileSystemException
    {
        // Set the replicator and temporary file store (use the same component)
        final DefaultFileReplicator replicator = createDefaultFileReplicator();
        setReplicator(new PrivilegedFileReplicator(replicator));
        setTemporaryFileStore(replicator);

        /* replaced by findClassLoader
        if (classLoader == null)
        {
            // Use default classloader
            classLoader = getClass().getClassLoader();
        }
        */

        if (configUri == null)
        {
            // Use default config
            final URL url = getClass().getResource(CONFIG_RESOURCE);
            if (url == null)
            {
                throw new FileSystemException("vfs.impl/find-config-file.error", CONFIG_RESOURCE);
            }
            configUri = url;
        }

        // Configure
        configure(configUri);

        // Configure Plugins
        configurePlugins();

        // Initialise super-class
        super.init();
    }

Issue Links

• relates to: VFS-621 Add API VFS.setManager(FileSystemManager)