Here's a class I came across while trying to solve a problem I had recently. Its a 'hack' so to speak, but it does work well. I have an app that uses the Comm API with java. The issue I had was the nusance of installing the app. You had to copy a few files to the jre and then set some classpath stuff. Not a big deal per se, but annoying, especially when I wanted a simple drag and drop solution.
This class helped provide that, by allowing me to add the comm.jar at runtime without having to make a batch file or modify the environment variables.
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| import java.io.*; import java.net.*; import java.lang.reflect.*;
public class ClassPathHacker {
private static final Class[] parameters = new Class[] { URL.class };
public static void addFile(String s) throws IOException { File f = new File(s); addFile(f); } public static void addFile(File f) throws IOException { addURL(f.toURL()); }
public static void addURL(URL u) throws IOException {
URLClassLoader sysloader = (URLClassLoader) ClassLoader.getSystemClassLoader(); Class sysclass = URLClassLoader.class;
try { Method method = sysclass.getDeclaredMethod("addURL", parameters); method.setAccessible(true); method.invoke(sysloader, new Object[] { u }); } catch (Throwable t) { t.printStackTrace(); throw new IOException("Error, could not add URL to system classloader"); }
} } |
I don't take credit for this, I came across it at java.net on the forums.
Regards,
Dr. A>