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POfindbugs report wrong line number and suppress error?
 

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  1. POfindbugs report wrong line number and suppress error?
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    <p>I have a java class which use System.GC() to calculate memory usage. However when I run findbugs, it always report wrong line number. Question 1: I ran this with intellij findbugs plugin as well as findbugs native GUI. Same result. Am I doing something wrong here?</p> <ol> <li><p>util.MemoryTestBench.lotsOfGC() forces garbage collection; extremely dubious except in benchmarking code Class: MemoryTestBench (util) Line: 35 - 35 ====> which is Thread.sleep(100) ????????</p></li> <li><p>Dead store to handle Class: MemoryTestBench (util) Line: 23 - 23 ====> which is return usedMemory() - prevUsedMemory ?????</p></li> </ol> <p>Question 2: how can I suppress error DM_GC ? I tried @SuppressWarnings which didn't work.</p> <p>test code is as follows:</p> <pre><code>package util; import java.util.Collections; import java.util.HashMap; import java.util.Hashtable; import java.util.Map; import java.util.concurrent.ConcurrentHashMap; import java.util.concurrent.locks.ReentrantLock; import edu.umd.cs.findbugs.annotations.SuppressWarnings; public class MemoryTestBench { @SuppressWarnings (value = "DM_GC", justification = "call GC to measure memory size") public static long calculateMemoryUsage(ObjectFactory factory) { Object handle = factory.makeObject(); long prevUsedMemory = usedMemory(); handle = null; lotsOfGC(); prevUsedMemory = usedMemory(); handle = factory.makeObject(); lotsOfGC(); return usedMemory() - prevUsedMemory; } private static long usedMemory() { return Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory(); } private static void lotsOfGC() { for (int i = 0; i &lt; 20; i++) { System.gc(); try { Thread.sleep(100); } catch (InterruptedException e) { Thread.currentThread().interrupt(); } } } public static void showMemoryUsage(ObjectFactory factory) { long mem = calculateMemoryUsage(factory); System.out.println( factory.getClass().getSimpleName() + " produced " + factory.makeObject().getClass().getSimpleName() + " which took " + mem + " bytes"); } public static void main(String[] args) { showMemoryUsage(new BigConcurrentHashMapFactory()); } } </code></pre>
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