Android - Installing Apache Commons VFS - Issues

Question

I'm hoping to use the Apache Commons VFS library in my Android project and have downloaded the relevant files from http://commons.apache.org/vfs/download_vfs.cgi. However. I'm getting some issues.

I've copied the commons-vfs2-2.0.jar file into a /libs/ subdirectory of my android project and referenced it in the java build path in Eclipse. I have also referenced the Commons Logging library which is used by Commons VFS (http://commons.apache.org/vfs/download.html).

Everything compiles fine, but as soon as I try the following line of code

FileSystemManager fsManager = VFS.getManager();

I get an exception. Here's the stack trace:

02-06 16:22:29.724: ERROR/Fatal Error(20515): Could not create a file system manager   of class "org.apache.commons.vfs2.impl.StandardFileSystemManager".
02-06 16:22:29.724: ERROR/Fatal Error(20515): org.apache.commons.vfs2.FileSystemException: Could not create a file system manager of class "org.apache.commons.vfs2.impl.StandardFileSystemManager".
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at org.apache.commons.vfs2.VFS.createManager(VFS.java:99)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at org.apache.commons.vfs2.VFS.getManager(VFS.java:50)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at gymApp.gymAppPackage.Utility.test(Utility.java:391)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at gymApp.gymAppPackage.HomeActivity.onCreate(HomeActivity.java:51)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2466)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2519)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at android.app.ActivityThread.access$2200(ActivityThread.java:123)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1870)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at android.os.Handler.dispatchMessage(Handler.java:99)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at android.os.Looper.loop(Looper.java:123)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at android.app.ActivityThread.main(ActivityThread.java:4370)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at java.lang.reflect.Method.invokeNative(Native Method)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at java.lang.reflect.Method.invoke(Method.java:521)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at dalvik.system.NativeStart.main(Native Method)
02-06 16:22:29.724: ERROR/Fatal Error(20515): Caused by: org.apache.commons.vfs2.FileSystemException: Could not load VFS configuration from "jar:file:/data/app/gymApp.gymAppPackage.apk!/org/apache/commons/vfs2/impl/providers.xml".
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at org.apache.commons.vfs2.impl.StandardFileSystemManager.configure(StandardFileSystemManager.java:199)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at org.apache.commons.vfs2.impl.StandardFileSystemManager.init(StandardFileSystemManager.java:123)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at java.lang.reflect.Method.invokeNative(Native Method)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at java.lang.reflect.Method.invoke(Method.java:521)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at org.apache.commons.vfs2.VFS.createManager(VFS.java:88)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     ... 16 more
02-06 16:22:29.724: ERROR/Fatal Error(20515): Caused by: org.apache.commons.vfs2.FileSystemException: Could not create file provider of class "org.apache.commons.vfs2.provider.local.DefaultLocalFileProvider".
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at org.apache.commons.vfs2.impl.StandardFileSystemManager.createInstance(StandardFileSystemManager.java:490)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at org.apache.commons.vfs2.impl.StandardFileSystemManager.addProvider(StandardFileSystemManager.java:371)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at org.apache.commons.vfs2.impl.StandardFileSystemManager.configure(StandardFileSystemManager.java:270)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at org.apache.commons.vfs2.impl.StandardFileSystemManager.configure(StandardFileSystemManager.java:195)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     ... 20 more
02-06 16:22:29.724: ERROR/Fatal Error(20515): Caused by: java.lang.ClassNotFoundException: org.apache.commons.vfs2.provider.local.DefaultLocalFileProvider in loader dalvik.system.PathClassLoader@400264d8
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:243)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at java.lang.ClassLoader.loadClass(ClassLoader.java:573)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at java.lang.ClassLoader.loadClass(ClassLoader.java:532)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     at org.apache.commons.vfs2.impl.StandardFileSystemManager.createInstance(StandardFileSystemManager.java:485)
02-06 16:22:29.724: ERROR/Fatal Error(20515):     ... 23 more

It seems like something basic is wrong with the installation, but I'm not sure what it is (Java is not my first language ;). Is there something special that needs to be done given that it is an Android project? Any pointers would be much appreciated.

Answer 1

I had exactly the same problem.

I got hold of the commons-vfs source code and traced the error through the code into the plugin initialisation - basically, our S3 provider plugin was being initialised, even though it wasn’t needed. Some funky class loader was spotting vfs-providers.xml in the S3 JAR and trying to initialise it, even though the URL didn’t require the plugin.

Once I removed the S3 provider JAR from the WEB-INF/lib directory, it all worked fine.