Loading Jar files at runtime

I have the following code that looks jar files in a directory and looks contents in it and then load. Can you pls help me how I can change it to just loop for jar files and those jar files are loaded.

I have the following code in a class that extends URLClassLoader.

public void loadFile() {

try {

URL [] urls = getURLs();

for(int i=0;i<urls.length;i++) {

String path = urls.getPath();

System.out.println("URL PATH :"+path);

JarInputStream jis = new JarInputStream(new FileInputStream(path));

JarEntry entry = jis.getNextJarEntry();

int loadedCount = 0, totalCount = 0;

while (entry != null) {

String name = entry.getName();

if (name.endsWith(".class")) {

totalCount++;

name = name.substring(0, name.length() - 6);

name = name.replace('/', '.');

System.out.print("> " + name);

try {

loadClass(name);

System.out.println("\t- loaded");

loadedCount++;

} catch (Throwable e) {

System.out.println("\t- not loaded");

System.out.println("\t " + e.getClass().getName() + ": " + e.getMessage());

}

}

entry = jis.getNextJarEntry();

}

System.out.println("\n");

System.out.println("Summary:");

System.out.println("\tLoaded:\t" + loadedCount);

System.out.println("\tFailed:\t" + (totalCount - loadedCount));

System.out.println("\tTotal:\t" + totalCount);

}

}

catch(Exception e) {

e.printStackTrace();

}

}

I don't want to do the code in bold. I have some 50 jars in the folder.

Thanks for your help.

Regards,

Kapil

jar_filesa at 2007-7-12 17:36:40 >

> Why are you doing this? The JVM will load classes

> from the classpath for you. What's the bigger picture?

Only time I've ever needed to do this was for a plugin interface, so that the user could just drop properly created .jar files in the plugins directory and have the application load them all.

It was such a pain in the butt that I eventually just changed the loading script into one that enumerated all the .jar files in the plugins directory and appended them into the classpath.

kevjavaa at 2007-7-12 17:36:40 >

Hi,

Due to performance, I don't want to load every class from jar file. Can I avoid the loop for class file with in the jar file loop. I can just say, from this folder please include all jar files with in this folder in the classpath at runtime. Due to requirement i need to do that in run time, Not at the beginning of starting application where we set the classpath for the application.

Thanks,

Kapil

jar_filesa at 2007-7-12 17:36:40 >

> Could anyone help me how to put jar files in the

> classpath at runtime without loading individual class

> files. I want to put certain jar with traditional

> classpath setting and certain during runtime that are

> lying in a directory.

It's not 100% clear what you're after. You can use URLClassLoader to add arbitrary entries to the classpath at runtime, which may or may not be what you're looking for. I can see from your code that you already know how to do this, which leads me to think maybe you're looking for something else, but quite what I don't know. The JVM won't load a class until something tries to use it, or you explicitly do so with either a classloader or Class.forName

georgemca at 2007-7-12 17:36:40 >