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POHow to fix the Findbugs issue "Null value is guaranteed to be dereferenced" NP_GUARANTEED_DEREF
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copied!<p>Hi I have got some code that is reported as having the NP_GUARANTEED_DEREF issue by Findbugs. Now looking at my code I don't quite understand what is wrong with it, can anyone suggest what the problem is. </p> <pre><code>public void test() { String var = ""; int index = 2; if (index == -1) { var = String.class.getName(); if (var.length() == 0) { var = null; } } else { var = Integer.class.getName(); if (var.length() == 0) { var = null; } } if (var == null) {// FINBUGS reports on this line NP_GUARANTEED_DEREF /* * There is a statement or branch that if executed guarantees that a value * is null at this point, and that value that is guaranteed to be * dereferenced (except on forward paths involving runtime exceptions). */ throw new NullPointerException("NULL"); } } </code></pre> <p>Now drilling into the Error in Findbugs it highlights the two assignments to <code>var = null;</code> as cause for the bug but I don't quite understand why. It is not like I am actually doing anything with the <code>var</code> object I am just doing a Null check. The example is taken from real production code but stripped of anything that wasn't needed to reproduce the error. What I am wondering if this is a false positive or not. And if not what would be an appropriate fix.</p> <p>Here is the link to the Findbugs Bug Detail: <a href="http://findbugs.sourceforge.net/bugDescriptions.html#NP_GUARANTEED_DEREF" rel="nofollow">http://findbugs.sourceforge.net/bugDescriptions.html#NP_GUARANTEED_DEREF</a></p> <p>[UPDATE] After recieving some feedback on this issue I have now logged this as a False Positive in the Findbugs Bugtracker on Sourceforge the link is <a href="https://sourceforge.net/tracker/?func=detail&aid=3277814&group_id=96405&atid=614693" rel="nofollow">https://sourceforge.net/tracker/?func=detail&aid=3277814&group_id=96405&atid=614693</a></p> <p>Conversation about the problem will continue there.</p>

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