Dragon seems not working

[eldysha]

Hi,
when I set up the Dragon XML configuration I get an error, I thought it was a problem in the XML file, hence I tried the "Abt-Buy-Dragon.xml" in the test folder "\src\test\resources" (adapting the paths), but it still returns me the same error.

The error is the following:

9:30:46.897 [qtp228450622-21] [] INFO org.aksw.limes.core.controller.Server:280 - Uploaded file 'Abt-Buy-Dragon.xml' saved as 'C:\Users\owner.server-storage\limes_cfg_5701470522682598660.xml'
19:30:46.951 [ForkJoinPool.commonPool-worker-3] [5701470522682598660] INFO org.aksw.limes.core.io.cache.HybridCache:115 - Checking for file C:\Users\owner\cache-1768654625.ser
19:30:46.971 [ForkJoinPool.commonPool-worker-3] [5701470522682598660] INFO org.aksw.limes.core.io.cache.HybridCache:132 - No cached data found for abt
19:30:46.977 [ForkJoinPool.commonPool-worker-3] [5701470522682598660] INFO org.aksw.limes.core.io.query.QueryModuleFactory:18 - Generating reader
19:30:47.041 [ForkJoinPool.commonPool-worker-3] [5701470522682598660] INFO org.aksw.limes.core.io.query.CsvQueryModule:81 - Retrieved 1081 statements
19:30:47.045 [ForkJoinPool.commonPool-worker-3] [5701470522682598660] INFO org.aksw.limes.core.io.cache.HybridCache:316 - Serializing 1081 objects to C:\Users\owner\cache-1768654625.ser
19:30:47.381 [ForkJoinPool.commonPool-worker-3] [5701470522682598660] INFO org.aksw.limes.core.io.cache.HybridCache:115 - Checking for file C:\Users\owner\cache-1987594183.ser
19:30:47.385 [ForkJoinPool.commonPool-worker-3] [5701470522682598660] INFO org.aksw.limes.core.io.cache.HybridCache:132 - No cached data found for buy
19:30:47.387 [ForkJoinPool.commonPool-worker-3] [5701470522682598660] INFO org.aksw.limes.core.io.query.QueryModuleFactory:18 - Generating reader
19:30:47.409 [ForkJoinPool.commonPool-worker-3] [5701470522682598660] INFO org.aksw.limes.core.io.query.CsvQueryModule:81 - Retrieved 1092 statements
19:30:47.412 [ForkJoinPool.commonPool-worker-3] [5701470522682598660] INFO org.aksw.limes.core.io.cache.HybridCache:316 - Serializing 1092 objects to C:\Users\owner\cache-1987594183.ser
19:30:47.856 [ForkJoinPool.commonPool-worker-3] [5701470522682598660] ERROR org.aksw.limes.core.ml.algorithm.dragon.FitnessFunctions.GiniIndex:175 - Node has no parent. This should not happen! Returning null
19:30:47.873 [ForkJoinPool.commonPool-worker-3] [5701470522682598660] INFO org.aksw.limes.core.ml.algorithm.dragon.Dragon:312 - FULL:

Classifier not set yet
19:30:47.907 [ForkJoinPool.commonPool-worker-3] [5701470522682598660] INFO org.aksw.limes.core.ml.algorithm.dragon.Dragon:315 - PRUNED:

Classifier not set yet
java.util.concurrent.CompletionException: java.lang.NullPointerException
at java.base/java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:314)
at java.base/java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:319)
at java.base/java.util.concurrent.CompletableFuture$UniAccept.tryFire(CompletableFuture.java:718)
at java.base/java.util.concurrent.CompletableFuture$Completion.exec(CompletableFuture.java:479)
at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:290)
at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1016)
at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1665)
at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1598)
at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:177)
Caused by: java.lang.NullPointerException
at org.aksw.limes.core.ml.algorithm.dragon.DecisionTree.getPathString(DecisionTree.java:263)
at org.aksw.limes.core.ml.algorithm.dragon.DecisionTree.calculatePathKeys(DecisionTree.java:187)
at org.aksw.limes.core.ml.algorithm.dragon.DecisionTree.getTotalLS(DecisionTree.java:279)
at org.aksw.limes.core.ml.algorithm.dragon.Dragon.learn(Dragon.java:317)
at org.aksw.limes.core.ml.algorithm.SupervisedMLAlgorithm.learn(SupervisedMLAlgorithm.java:42)
at org.aksw.limes.core.controller.MLPipeline.execute(MLPipeline.java:69)
at org.aksw.limes.core.controller.Controller.getMapping(Controller.java:207)
at org.aksw.limes.core.controller.Server.lambda$handleSubmit$4(Server.java:309)
at java.base/java.util.concurrent.CompletableFuture$UniAccept.tryFire(CompletableFuture.java:714)
... 6 more

Am I missing something in the implementation or is a bug?

Many thanks!

[eldysha]

After some testing, I found out that this error appears only after 2 executions of the DRAGON algorithm.
Which means that I am able to run a DRAGON matching using the CLI on port:8080, but if I want to perform again a DRAGON algorithm I have to close the CLI and restart it.
In this way, I was able to bypass the error.

[kvndrsslr]

Thanks for reporting this, seems like state is being kept statically, which is bad for the server context indeed .