NullPointerException error with Java

I'm getting this error message when trying to run some unit tests. How do I fix this?

Error using print (line 102)
There was a problem while generating the output: Java exception occurred:
java.lang.NullPointerException

	at com.mathworks.hg.print.FOPPDFVectorStrategy.endJob(FOPPDFVectorStrategy.java:127)

	at com.mathworks.hg.util.HGVectorOutputHelper.close(HGVectorOutputHelper.java:239)


Error in saveas (line 168)
        print( h, name, ['-d' dev{i}] )

Error in executeUnitTests (line 392)
                    saveas(fig,['.\test\unit\output\' StateFlowModelName '_UT_' t '\' Current_Test_Name '\'
                    Caption '.pdf']);
                

[Prashant Nirmal]

Make sure your Java environment is correctly configured.

Configure Your Java Environment

If the issue persists after configuring Java then uninstall MATLAB completely and install it again.