i have try this code but it it not working.though all the field are null but it still take action.code is given below : if(((f_NameText.getText())!=null)&&((l_NameText.getText())!=null)&&((u_NameText.getText())!=null)&&((newMembersPassword.getPassword())!=null))
       {newMembersButton.addActionListener(new NewJoinButtonHandler());}