Exception in thread "main" java.util.concurrent.RejectedExecutionException

[wendysyn89]

I was running Semafor on a dataset with 404291 sentences.

However it stopped at sentence 12339 with the following errors.

Exception in thread "main" java.util.concurrent.RejectedExecutionException: Task java.util.concurrent.FutureTask@277c0f21 rejected from java.util.concurrent.ThreadPoolExecutor@6073f712[Shutting down, pool size = 50, active threads = 50, queued tasks = 17, completed tasks = 12335]
at java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:2047)
at java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:823)
at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1369)
at java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:134)
at edu.cmu.cs.lti.ark.fn.Semafor.runParser(Semafor.java:195)
at edu.cmu.cs.lti.ark.fn.Semafor.main(Semafor.java:100)

Thanks for any advice and helps.