classloader

I'm working with a Java sort-of-application-server (Smartfox) which can run multiple applications ("extensions") but has a very inconvenient classpath setup to go along with it, along with issues when trying to use SLF4J. To work around that I'd like to wrap my applications in their own classloaders. Such a containing classloader should be much like Tomcat's, in that it Can load classes from a directory containing JARs. Prefers classes from its own classpath over those from the parent Is there a library somewhere that has such a classloader I can just "drag and drop" in my project? If not,

I have code that is running correctly on a development machine but throws a NullPointerException when installed in a production environment. The line that throws the exception is the following: MyClass.class.getClassLoader().getResource("").getPath(); So I split this into multiple lines of code to see exactly which call was returning null, like this: ClassLoader cl = MyClass.class.getClassLoader(); URL url = cl.getResource(""); String path = url.getPath(); Now the url.getPath() call is throwing the NullPointerException, meaning that cl.getResource("") is returning null. Can anyone tell me how

When does the class get loaded in the JVM? Do they get loaded on the server start up or when there is a reference for the class? My assumption is that all the class gets loaded as the server like jboss starts up but then there is something called lazyloading. Also what is actually meant by loading? Does it mean there is this .class in the JVM memory along with all the methods, variables including instance, static variables methods and are available for execution. I Know that ClassLoader locates the bytecodes for a Java class that needs to be loaded, reads the bytecodes, checks the refrencces

So, I have an installed extension (see http://docs.oracle.com/javase/tutorial/ext/basics/index.html ) which I can see in Eclipse. I've written a simple rcp application that tries to create an instance of a class in this extension. However, although everything compiles ok, I'm getting a NoClassDefFoundError when creating the instance. I'm assuming this has something to do with OSGi because I can run a simple java application that creates the instance fine. Any suggestions would be really appreciated. Thanks I've found another solution which is to set the parent classloader to the 'ext'

The first opening of a new JInternalFrame in my Swing interface takes some time. According to the profiler, most of this time is spent in the Classloader.loadClass() method. I understand that it loads classes dynamically when needed and indeed the next time I open the same frame, it is much faster. This application has a login screen, and then a time with an empty desktoppane before the user opens one of those internal frames. I figure that since I have some "down time", I could use it to preload some common classes in background, so that when the user actually opens an internal frame, it goes

I'm very confused about the JBoss class loader. Can any one describe in details how the class loader works, exactly? I only have to do one thing... If a WAR doesn't find a class with its own classloader, he delegates the search to its parent classloader which must be the EAR's. What changes should I have to do in my application for the above? Please reply as soon as possible. Thank you. In continuation of our discussion in the comments, I noticed the following JBoss feature request. https://issues.jboss.org/browse/JBAS-4037 It looks like JBoss 4 is not fully Java EE5 compatible, however later