Dynamic Class Loading in GCJ

Thu Dec 25 10:39:00 GMT 2008

Tushar kant wrote:
> Hi! I'm writing an application in Java using GCJ and would like to
> add a plug-in feature to it. I have searched the internet a lot but
> couldn't find a way to dynamically load .class\.so files dynamically.
> I would really appreciate it if someone could help me on this.

Here's a really simple example:
foo.java:
import java.net.*;
public class foo
{
 public static void main(String[] argv)
 throws Exception
 {
 ClassLoader l
 = (new URLClassLoader
	 (new URL[] {new URL("gcjlib://"
			 + System.getProperty("user.dir")
			 + "/libpop.so")}));
 Class<?> C = l.loadClass("pop");
 C.newInstance();
 }
}
pop.java:
public class pop
{
 pop()
 {
 System.out.println("Cooee!");
 }
}
 $ gcj foo.java -o foo --main=foo
 $ gcj -findirect-dispatch -Wl,-Bsymbolic -shared pop.java -o libpop.so -fpic
 $ ./foo
Cooee!
Gcj has lots of other class loading mechanisms that you might find useful.
All this, and more, is explained in the gcj documentation.