DS results in Java exception

[henryYHC]

Java throws illegal argument exception when trying to sort List<ObjectDoublePair<double[]>>:

java.lang.IllegalArgumentException: Comparison method violates its general contract!
at java.util.TimSort.mergeHi(TimSort.java:895)
at java.util.TimSort.mergeAt(TimSort.java:512)
at java.util.TimSort.mergeCollapse(TimSort.java:437)
at java.util.TimSort.sort(TimSort.java:241)
at java.util.Arrays.sort(Arrays.java:1512)
at java.util.ArrayList.sort(ArrayList.java:1454)
at java.util.Collections.sort(Collections.java:175)
at edu.emory.clir.clearnlp.relation.parameter.MainEntityExtractorParamenterSearch.search(MainEntityExtractorParamenterSearch.java:100)
at edu.emory.clir.clearnlp.relation.parameter.MainEntityExtractorParamenterSearch.run(MainEntityExtractorParamenterSearch.java:82)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)