Java SE (Java Platform, Standard Edition)

Hey guys, I'm used to programming under windows but i wanted to give it a try under linux, there are a few things that can't seem to compile well and I don't know what may be going on.
This simple code

import javax.swing.JOptionPane;

public class Exam {

public static void main(String args [])
{
JOptionPane.showMessageDialog(null, "This is a test");
}
}

will give me this error:

Exception in thread "main" java.awt.AWTError: Cannot load AWT toolkit: gnu.java.awt.peer.gtk.GtkToolkit
at java.awt.Toolkit.getDefaultToolkit(libgcj.so.70)
at java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment(libgcj.so.70)
at java.awt.Window.<init>(libgcj.so.70)
at java.awt.Frame.<init>(libgcj.so.70)
at java.awt.Frame.<init>(libgcj.so.70)
at javax.swing.SwingUtilities$OwnerFrame.<init>(libgcj.so.70)
at javax.swing.SwingUtilities.getOwnerFrame(libgcj.so.70)
at javax.swing.JOptionPane.<clinit>(libgcj.so.70)
at java.lang.Class.initializeClass(libgcj.so.70)
at leer.i(leer.java:51)
at american.main(american.java:12)
Caused by: java.lang.UnsatisfiedLinkError: libgtkpeer: libgtkpeer.so: cannot open shared object file: No such file or directory
at java.lang.Runtime._load(libgcj.so.70)
at java.lang.Runtime.loadLibrary(libgcj.so.70)
at java.lang.System.loadLibrary(libgcj.so.70)
at gnu.java.awt.peer.gtk.GtkToolkit.<clinit>(libgcj.so.70)
at java.lang.Class.initializeClass(libgcj.so.70)
at java.lang.Class.forName(libgcj.so.70)
at java.awt.Toolkit.getDefaultToolkit(libgcj.so.70)
...10 more

btw, error that i dont get when running it under windows, anyone can help? thanks