Exception thrown after overriding update on EntityHome class

[reyjexter.reyjexter.gmail.com]

exception thrown after overriding update method of EntityHome. I'm using a custom hibernate validator that checks if a username already exist on my database.

The entity class (only partial):

@Length(min=3, max=32, message="Username should be 3-32 characters")
@NotNull
@UsernameExist
public String getUsername() {
     return username;
}

public void setUsername(String username) {
     this.username = username;
}

The user home class:

@Override
public String update() {
     // cant seem to use hibernate validator for a very complex validation rules such as this one
     User user = getInstance();
     String oldPassword = user.getOldPassword();
     String newPassword = user.getNewPassword();
     String confirmNewPassword = user.getConfirmNewPassword();
     
     if(oldPassword.length() != 0 || newPassword.length() != 0 || confirmNewPassword.length() != 0 ) {
          if(!user.getPassword().equals(oldPassword)) {
               getFacesMessages().add("Old password given not correct");
               return null;
          }
          if(!newPassword.equals(confirmNewPassword)) {
               getFacesMessages().add("New password and confirmation password did not matched");
               return null;
          } 
               getInstance().setPassword(getInstance().getNewPassword());
          
     }
     
     return super.update();
}

and finally, the username exist validator

public boolean isValid(Object value) {
     UserHome userHome = (UserHome) Component.getInstance("userHome");
     System.out.println("RUNNING VALIDATOR...");
     User user = userHome.findUser(value.toString());
     
     // return true if no user with the given value was found
     if(user == null) {
          return true;
     } 
     
     // return true if the user retrieved is equals to the current instance in home
     if(user.getId() == userHome.getInstance().getId()) {
          return true;
     }
     
     // return false if the username exist on our database
     return true;
}

I noticed that the validator is called twice. I'm not sure but i think the part where i try to replace the value of the user home instance (in the user home class) causes entity be validated. see the line below:

getInstance().setPassword(getInstance().getNewPassword());

the exception btw looks like this:

2008-02-29 00:14:53,437 FATAL [javax.enterprise.resource.webcontainer.jsf.application] java.lang.reflect.InvocationTargetException
javax.faces.el.EvaluationException: java.lang.reflect.InvocationTargetException
     at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:91)
     at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:91)