intercept NullPointerException and rethrow it with (marginally) comprehensible error message when an attempt to get class source code location fails

git-svn-id: file:///humgen/gsa-scr1/gsa-engineering/svn_contents/trunk@854 348d0f76-0448-11de-a6fe-93d51630548a

java/src/org/broadinstitute/sting/utils/JVMUtils.java

@@ -40,6 +40,9 @@ public class JVMUtils {
             // a URISyntaxException here must be an IO error; wrap as such.
             throw new IOException(ex);
         }
+        catch ( NullPointerException ne ) {
+        	throw new IOException("Can not extract code source location for "+clazz.getName());
+        }
     }
 
     /**