Condition with Swing Options

Question

I get NullPointerException when I press the CANCEL Option in my Swing.

Code:

while(!input.equals(CANCEL_OPTION));

And I get a message that it says incompatible types....

And here's my full code..

do
    {
    input=JOptionPane.showInputDialog("Enter a String.");


    for(int i =input.length()-1;i>=0;i--)
    {           
        result = result + (input.charAt(i));
        disp.append("\n").append(result);
    }       

    JOptionPane.showMessageDialog(null,input+"\n"+disp+"\n"+"\n"+result);
    input="";
    disp.setLength(0);
    result="";
    }
    while(!input.equals(CANCEL_OPTION));

And the error code or something..

Exception in thread "main" java.lang.NullPointerException
at Reverse.main(Reverse.java:15)
Java Result: 1

Answer 1

just use try catch statement..

try
    {
    do
    {
        //your codesss......
    }
    while(!input.equals(null));
    }
    catch(Exception ex)
    {
     ////code..
    }

hope it help.