Java

1. Choose the correct forum for your message. Posting a VB.NET question in the C++ forum will end in tears.
    
   
2. Be specific! Don't ask "can someone send me the code to create an application that does 'X'. Pinpoint exactly what it is you need help with.
    
   
3. Keep the subject line brief, but descriptive. eg "File Serialization problem"
    
   
4. Keep the question as brief as possible. If you have to include code, include the smallest snippet of code you can.
    
   
5. Be careful when including code that you haven't made a typo. Typing mistakes can become the focal point instead of the actual question you asked.
    
   
6. Do not remove or empty a message if others have replied. Keep the thread intact and available for others to search and read. If your problem was answered then edit your message and add "[Solved]" to the subject line of the original post, and cast an approval vote to the one or several answers that really helped you.
    
   
7. If you are posting source code with your question, place it inside <pre></pre> tags. We advise you also check the "Encode HTML tags when pasting" checkbox before pasting anything inside the PRE block, and make sure "Ignore HTML tags in this message" check box is unchecked.
    
   
8. Be courteous and DON'T SHOUT. Everyone here helps because they enjoy helping others, not because it's their job.
    
   
9. Please do not post links to your question in one forum from another, unrelated forum (such as the lounge). It will be deleted.
    
   
10. Do not be abusive, offensive, inappropriate or harass anyone on the boards. Doing so will get you kicked off and banned. Play nice.
     
    
11. If you have a school or university assignment, assume that your teacher or lecturer is also reading these forums.
     
    
12. No advertising or soliciting.
     
    
13. We reserve the right to move your posts to a more appropriate forum or to delete anything deemed inappropriate or illegal.

1. Read the question carefully
    
   
2. Understand that English isn't everyone's first language so be lenient of bad spelling and grammar
    
   
3. If a question is poorly phrased then either ask for clarification, ignore it, or mark it down. Insults are not welcome
    
   
4. If the question is inappropriate then click the 'vote to remove message' button
   

 listener = new ListSelectionListener() {
 
            @Override
            public void valueChanged(ListSelectionEvent e) {
    
          index = imageList.getSelectedIndex();
            imageList.setSelectedIndex(index);
                  o = imageList.getSelectedValue();
                if (o instanceof BufferedImage) {
                    imageView.setIcon(new ImageIcon((BufferedImage)o));
                   
            }
 
            }
  
        };
 
       imageList.addListSelectionListener(listener);
 

public void nextimage() 
      {
         index ++;
 
imageList.addListSelectionListener(listener);
 
       imageList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION); 
       imageList.setSelectedIndex(index); -----here is error: Null Pointer Exception
 
}