try {
  String s = null;
  s.toString(); // sがnull
}
catch(NullPointerException e) {

    e.printStackTrace();
}

java.lang.NullPointerException
 at CodeSnippet_19.run(CodeSnippet_19.java:5)
 at org.eclipse.jdt.internal.debug.ui.snippeteditor.ScrapbookMain1.eval(ScrapbookMain1.java:20)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
 at java.lang.reflect.Method.invoke(Unknown Source)
 at org.eclipse.jdt.internal.debug.ui.snippeteditor.ScrapbookMain.evalLoop(ScrapbookMain.java:54)
 at org.eclipse.jdt.internal.debug.ui.snippeteditor.ScrapbookMain.main(ScrapbookMain.java:35)