Thread: NullPointerException when canceling JOptionPane.showInputDialog

Hello

I am a beginner in java, so I guess my question might sound trivial to some.
I am writing some code to execute the setup of some computations. The computation needs the definition of 'continuum'.
First, I am collecting the continuum. If there are no continuum define, I am asking the name to the the user.
Everything is working fine, except that if I choose the "cancel" button, I am getting a null pointer exception while exiting.
So my question is: how to properly cancel and exit?
Thanks for any help

Integer contMgr =
	simulation_0.getContinuumManager().getChildrenCount();
 
	if (contMgr == 0)
            {
            continuum= JOptionPane.showInputDialog("Enter the name of the Continuum", "" );
                            //-----------------------------------------------------//
                            //	If the user use the 'Cancel' option, exit of the Macro	//
                            //----------------------------------------------------//
				if (continuum == null)
                                    {
                                    JOptionPane.showMessageDialog(null,
                                                                "Canceling the Computation Setup",
                                                                "Canceling",JOptionPane.WARNING_MESSAGE);
                                    return;
                                    }
            }
      else blalbalbala

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Review the code that executes after the 'Cancel' is selected. Something null is being processed by the exiting code, so check for the null and create a different path that avoids that result.