Calling IIOMetadata.getMetadataFormat() for a user supplied ImageReader plugin
(such as those offered by the JAI Image I/O Tools package) may throw an
exception depending on the caller's classloader. Here is a snippet from the
submitter's testcase that demonstrates the exception:

-----------------snip--------------------

ByteArrayOutputStream ostream = new ByteArrayOutputStream();
FileCacheImageOutputStream fcios = null;
try {
    fcios = new FileCacheImageOutputStream(ostream, null);
} catch(IOException ex) {
    System.err.println("There was a problem creating the
FileCacheImageOuputStream: "+ex.toString());
    return null;
}

Iterator writers =
    ImageIO.getImageWritersByFormatName("jpeg2000");
if(!writers.hasNext()) {
    System.err.print("No ImageWriter available for chosen output format");
    return null;
}

//Debugging output here to show class loader issue of
//getMetadataFormat() implementation.
try {
    System.err.println("java.system.class.loader =
"+System.getProperty("java.system.class.loader"));
    System.err.println("Loading class first way");
    Class cls =
Class.forName("com.sun.media.imageioimpl.plugins.jpeg2000.J2KMetadataFormat"
, true, this.getClass().getClassLoader());
    System.err.println("Loaded class first way: "+cls);
    System.err.println("Loading class second way");
    cls =
Class.forName("com.sun.media.imageioimpl.plugins.jpeg2000.J2KMetadataFormat"
, true, ClassLoader.getSystemClassLoader()); //This was
ImageFactory.java:150
    System.err.println("Loaded class second way: "+cls);
    Method meth = cls.getMethod("getInstance", null);
    System.err.println((IIOMetadataFormat) meth.invoke(null, null));
} catch(Exception ex) {
    System.err.println("There was a problem loading the native metadata");
    ex.printStackTrace();
}

--------------------------snip-----------------------------

And the output from executing this code:

-------------------output/exceptions-----------------------

java.system.class.loader = null
Loading class first way
Loaded class first way: class
com.sun.media.imageioimpl.plugins.jpeg2000.J2KMetadataFormat
Loading class second way
There was a problem loading the native metadata
java.lang.ClassNotFoundException:
com.sun.media.imageioimpl.plugins.jpeg2000.J2KMetadataFormat
at java.net.URLClassLoader$1.run(URLClassLoader.java:199)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:187)
at java.lang.ClassLoader.loadClass(ClassLoader.java:289)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:274)
at java.lang.ClassLoader.loadClass(ClassLoader.java:235)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:302)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:219)
at
com.gwha.hmi.service.objectgateway.handlers.ImageFactory.getTranscodedImageI
nputStream(ImageFactory.java:150)
at
com.gwha.hmi.service.objectgateway.handlers.VectorGraphicsHandler.getRasterI
mageInputStream(VectorGraphicsHandler.java:417)
at
com.gwha.hmi.service.objectgateway.handlers.VectorGraphicsHandler.getObjectI
nputStream(VectorGraphicsHandler.java:304)
at
com.gwha.hmi.service.objectgateway.ObjectGateway.openFileForReading(ObjectGa
teway.java:282)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39
)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl
.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:261)
at sun.rmi.transport.Transport$1.run(Transport.java:148)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Transport.java:144)
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:460)
at
sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:7
01)
at java.lang.Thread.run(Thread.java:534)
Error: One factory fails for the operation "ImageWrite"
Occurs in: javax.media.jai.ThreadSafeOperationRegistry
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39
)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl
.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at javax.media.jai.FactoryCache.invoke(FactoryCache.java:130)
at
javax.media.jai.OperationRegistry.invokeFactory(OperationRegistry.java:1682)
at
javax.media.jai.ThreadSafeOperationRegistry.invokeFactory(ThreadSafeOperatio
nRegistry.java:481)
at javax.media.jai.registry.RIFRegistry.create(RIFRegistry.java:340)
at javax.media.jai.RenderedOp.createInstance(RenderedOp.java:830)
at javax.media.jai.RenderedOp.createRendering(RenderedOp.java:878)
at javax.media.jai.RenderedOp.getRendering(RenderedOp.java:899)
at javax.media.jai.JAI.createNS(JAI.java:1103)
at javax.media.jai.JAI.create(JAI.java:977)
at
com.sun.media.jai.operator.ImageWriteDescriptor.create(ImageWriteDescriptor.
java:964)
at
com.gwha.hmi.service.objectgateway.handlers.ImageFactory.getTranscodedImageI
nputStream(ImageFactory.java:162)
at
com.gwha.hmi.service.objectgateway.handlers.VectorGraphicsHandler.getRasterI
mageInputStream(VectorGraphicsHandler.java:417)
at
com.gwha.hmi.service.objectgateway.handlers.VectorGraphicsHandler.getObjectI
nputStream(VectorGraphicsHandler.java:304)
at
com.gwha.hmi.service.objectgateway.ObjectGateway.openFileForReading(ObjectGa
teway.java:282)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39
)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl
.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:261)
at sun.rmi.transport.Transport$1.run(Transport.java:148)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Transport.java:144)
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:460)
at
sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:7
01)
at java.lang.Thread.run(Thread.java:534)
Caused by: java.lang.IllegalStateException: Can't obtain format
at
javax.imageio.metadata.IIOMetadata.getMetadataFormat(IIOMetadata.java:388)
at
com.sun.media.imageioimpl.plugins.jpeg2000.J2KMetadata.<init>(J2KMetadata.ja
va:86)
at
com.sun.media.imageioimpl.plugins.jpeg2000.J2KMetadata.<init>(J2KMetadata.ja
va:151)
at
com.sun.media.imageioimpl.plugins.jpeg2000.J2KImageWriterCodecLib.write(J2KI
mageWriterCodecLib.java:277)
at
com.sun.media.jai.imageioimpl.ImageWriteCRIF.create(ImageWriteCRIF.java:555)
at
com.sun.media.jai.imageioimpl.ImageWriteCRIF.create(ImageWriteCRIF.java:205)
... 29 more
Caused by: java.lang.ClassNotFoundException:
com.sun.media.imageioimpl.plugins.jpeg2000.J2KMetadataFormat
at java.net.URLClassLoader$1.run(URLClassLoader.java:199)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:187)
at java.lang.ClassLoader.loadClass(ClassLoader.java:289)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:274)
at java.lang.ClassLoader.loadClass(ClassLoader.java:235)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:302)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:219)
at
javax.imageio.metadata.IIOMetadata.getMetadataFormat(IIOMetadata.java:383)
... 34 more