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NWDS 7.5 Error: Comparison method violates its general contract!

Hi all,

i came across a strange error last week and it cost me a lot of time and nerves. I had created a BPM model with custom tech tasks, as usual I imported some complex types from ESR and set them as in / output structure. When the structure changed and i tried to re-open the wizard for custom tech… nothing happened. I restarted NWDS several times, “reinstalled” it, tried different versions etc. I clicked the hell out of this button but nothing happened. The log gave me the same error every time:


I searched around in SCN for a solution but could not find any. So i was stalking a bit in the Eclipse community and found this Bug report:


According to this, the error occurs due to badly implemented comparators which where silently ignored in Java 1.6 but since 1.7 they crash. Because i can’t do any changes on the SAP Plugins, the workaround was quite simple. Allow the arrays util to use LegacyMergeSort. Just add “-Djava.util.Arrays.useLegacyMergeSort=true” to your ini file and it works again. Issue took so much time and the solution was that easy. I hope SAP is working on this one.

Have fun.



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