using testng on eclipse

This post provides a quick roadmap to start using testng on eclipse, since there is enourmous amount of documentation on web and it is hard to pick the most relevant ones..

• http://www.testng.org/doc/eclipse.html : quite well to start using the framework.
• https://khyatisehgal.wordpress.com/2014/08/24/java-lang-unsupportedclassversionerror-unsupported-major-minor-version-51-0-at/ : helps to solve the troubles encountered while following the first tutorial..
• https://www.youtube.com/watch?v=gFLpTjH9dlY : not too relevant, but it is a good seminar about testing on enterprise applications, so i wanted to share..

another tip: testng eclipse plugin version 6.9.5... (Update Site - http://beust.com/eclipse) supports JDK7 and 6.8.6 (Update Site - http://beust.com/eclipse-old/eclipse-6.8.6.20141201_2240) supports JDK6. 

Lucene tip

If you manually delete some files from the lucene index directory, than the next time you try to index you will get an error about the location being OUT-OF-SYNC. The error message may look like something like that:

 Entity com.mypackage.MyEntity Id 12345 Work Type org.hibernate.search.backend.UpdateLuceneWork  
 Entity com.mypackage.MyEntity Id 12346 Work Type org.hibernate.search.backend.UpdateLuceneWork  
 : org.apache.lucene.store.LockObtainFailedException: Lock obtain timed out: NativeFSLock@/path/to/index/com.mypackage.MyEntity/write.lock  
 at org.apache.lucene.store.Lock.obtain(Lock.java:84) [lucene-core-3.5.0.jar:3.5.0 1204425 - simon - 2011-11-21 11:20:12]  
 at org.apache.lucene.index.IndexWriter.(IndexWriter.java:1108) [lucene-core-3.5.0.jar:3.5.0 1204425 - simon - 2011-11-21 11:20:12]  
 at org.hibernate.search.backend.impl.lucene.IndexWriterHolder.createNewIndexWriter(IndexWriterHolder.java:127) [hibernate-search-engine-4.1.0.Final.jar:4.1.0.Final]  
 at org.hibernate.search.backend.impl.lucene.IndexWriterHolder.getIndexWriter(IndexWriterHolder.java:102) [hibernate-search-engine-4.1.0.Final.jar:4.1.0.Final]  
 at org.hibernate.search.backend.impl.lucene.AbstractWorkspaceImpl.getIndexWriter(AbstractWorkspaceImpl.java:119) [hibernate-search-engine-4.1.0.Final.jar:4.1.0.Final]  
 at org.hibernate.search.backend.impl.lucene.LuceneBackendQueueTask.applyUpdates(LuceneBackendQueueTask.java:99) [hibernate-search-engine-4.1.0.Final.jar:4.1.0.Final]  
 at org.hibernate.search.backend.impl.lucene.LuceneBackendQueueTask.run(LuceneBackendQueueTask.java:67) [hibernate-search-engine-4.1.0.Final.jar:4.1.0.Final]  
 at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) [rt.jar:1.7.0_03]  
 at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334) [rt.jar:1.7.0_03]  
 at java.util.concurrent.FutureTask.run(FutureTask.java:166) [rt.jar:1.7.0_03]  
 at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) [rt.jar:1.7.0_03]  
 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) [rt.jar:1.7.0_03]  
 at java.lang.Thread.run(Thread.java:722) [rt.jar:1.7.0_03]  

My solution to this situation, is clearing the OUT-OF-SYNC folder content, restart the server and reindex.
More practical solutions may exist, but that worked for me.. By the way, just deleting the write.lock file does not work here..
Another tip about the lock mechanism:
(from http://www.gossamer-threads.com/lists/lucene/java-user/261725 :)

The existence of the write.lock file has nothing to do with actual locking. The lock file is just a placeholder file (0 bytes) on which the lock during indexing is applied (the actual locking is done on this file using a fnctl). When indexing finishes, the lock is removed from this file, but the file stays alive. This was different in Lucene 3, where the lock was also removed. But this caused problems because of non-atomic file operations. Lock factory only checks the "lock on the file", not "the existence of the file as a lock".