return new JikesRVMDebugger(this);
return null;
  public IVMRunner getVMRunner(String mode) {    if (ILaunchManager.RUN_MODE.equals(mode)) {      return new JikesRVMRunner(this);    }     if (ILaunchManager.DEBUG_MODE.equals(mode)) {            // we'll try...      return new JikesRVMDebugger(this);          }    return null;  }