classloader

Assume I have a project K K depends lib.jar In lib.jar , there is a class named x.y.z.Foo If i create the same class x.y.z.Foo in K , then in this project when I create a instance of Foo , now will JVM use Foo in K rather than in lib.jar ? And if it's unstable or depends on something , how to make sure that Foo should use K 's version rather than lib.jar ? Java class loading behaviour in a standalone application (at least with no custom classloaders) is stable. Make sure that your k.jar (or path) comes before lib.jar in -cp java arg java -cp k.jar lib.jar ... or add dependencies to /META-INF

I want a mechanism that will allow to dynamically load and unload jars as well as calling an activator class in the jar. I don't want to use OSGi because of the cumbersome import/export mechanism. There's a project called the Java Plugin Framework that might be what you're looking for. On their web page it states the project is an attempt to match and extend Eclipse's pre-OSGI plugin architecture. It's a generic framework and isn't tied to SWT/desktop apps. You can use the ClassLoader to dynamically load classes from JAR files. When you have dynamically loaded the class, you can explicitly

I'm using the delayed_job plugin in Rails to do background processing, and I'm experiencing a hiccup in the 'agile development' I've been experiencing so far in Rails... Usually in rails if I hit an error / want to add some new functionality - I just add some code and refresh the page and the new code runs. With delayed_job, it seems like the job class isn't being reloaded... if a job fails and I go and fix the error and fire the job again, the old code runs again. Is there any way to make delayed_job load the newest version of the job class before invoking it? Just in case this has anything

I'm trying to tell the JVM to use my custom ClassLoader as default ClassLoader This is the VM argument i use to pick my class: -Djava.system.class.loader=JarClassLoader and this is the error i get Error occurred during initialization of VM java.lang.Error: java.lang.NoSuchMethodException: JarClassLoader.<init>(java.lang.ClassLoader) at java.lang.ClassLoader.initSystemClassLoader(Unknown Source) at java.lang.ClassLoader.getSystemClassLoader(Unknown Source) Caused by: java.lang.NoSuchMethodException: JarClassLoader.<init>(java.lang.ClassLoader) at java.lang.Class.getConstructor0(Unknown Source)

I want to do the following: try { Class.forName("MyClass"); } catch(ClassNotFoundException e) { ClassPool pool = ClassPool.getDefault(); CtClass cc = pool.makeClass("MyClass"); Class.forName("MyClass"); } I have tried it, but it doesn't seem to work always... It works in one context, but in the other the same code is crashing on the second "Class.forName("MyClass")"... Calling cc.toClass() always brings the correct class, and have tried cc.writeFile() but it makes no difference. Somehow, in some cases the second Class.forName finds the class, and in other cases it just breaks... Am I missing