java - ACM Interactors Freeze -

i'm trying make simple program swing , acm interactors. taken directly class handout, not function on computer. when run it, functions fine half second, briefly flashes, reloads, , button , text-field functionality lost. here's code:

import acm.program.*; import java.awt.event.*; import javax.swing.*;  public class textfieldexample extends consoleprogram {  public void init() {     namefield = new jtextfield(15);     add(new jlabel("name: "), south);     add(namefield, south);     namefield.addactionlistener(this); }  public void actionperformed(actionevent e) {     if (e.getsource() == namefield) {         println("hello, " + namefield.gettext());     } }  private jtextfield namefield; } 

if helps, i'm using java se 1.6 eclipse helios service release 2 on mid-2010 mac pro running mac osx 10.8.4

as workaround, in addition using java 1.5, add field north. also, may want extend graphicsprogram.

modified sscce:

import acm.program.*; import java.awt.event.*; import javax.swing.*;  public class textfieldexample extends graphicsprogram {      @override     public void init() {         namefield = new jtextfield(15);         add(new jlabel("name: "), north);         add(namefield, north);         namefield.addactionlistener(this);     }      @override     public void actionperformed(actionevent e) {         if (e.getsource() == namefield) {             println("hello, " + namefield.gettext());         }     }     private jtextfield namefield; }