weblogic.socket.NIOSocketMuxer

Today I will tell about one issue which I had to solve. It's about Weblogic 12c that loaded the CPU on 100%. With this in the logs were stuck threads. And when I investigated the thread dump I found this:

"ExecuteThread: '0' for queue: 'weblogic.socket.Muxer'" daemon prio=10 tid=0x00007fe20c420000 nid=0x58dc runnable [0x00007fe25c66d000]
   java.lang.Thread.State: RUNNABLE
	at sun.nio.ch.EPollArrayWrapper.epollWait(Native Method)
	at sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269)
	at sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:79)
	at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:87)
	- locked  (a sun.nio.ch.Util$2)
	- locked  (a java.util.Collections$UnmodifiableSet)
	- locked  (a sun.nio.ch.EPollSelectorImpl)
	at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:98)
	at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:102)
	at weblogic.socket.NIOSocketMuxer.selectFrom(NIOSocketMuxer.java:529)
	at weblogic.socket.NIOSocketMuxer.processSockets(NIOSocketMuxer.java:458)
	at weblogic.socket.SocketReaderRequest.run(SocketReaderRequest.java:30)
	at weblogic.socket.SocketReaderRequest.execute(SocketReaderRequest.java:43)
	at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:147)
	at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:119)