Question

I have the following code snippet

URL url = new File("c:/work/projects/jars/").toURI().toURL();
URL[] urls = new URL[]{url};
URLClassLoader child = new URLClassLoader(urls, this.getClass().getClassLoader());
URL res = child.findResource("temp.txt");
cls = child.loadClass("com.foo.adapter.sample.PluginImpl");

The jars folder contains a text file “temp.txt” and a jar file which contiains the PluginImpl class. The resource is loaded but the class is not.
When I extract the jar’s contents to the folder the class is getting loaded.
Where am I going wrong?

Answer 1

You have to add the JAR itself to the classpath. The JVM differentiates between resources and JARs. This should work:

URL url1 = new File("c:/work/projects/jars/").toURI().toURL(); // resources
URL url2 = new File("c:/work/projects/jars/myjar.jar").toURI().toURL(); // jar
URL[] urls = new URL[]{url1, url2};