### Environment * Dubbo version: v2.6.3 * Operating System version: ubuntu 18.04 * Java version: 10.0.1
### Step to reproduce this issue 1. create a new project with maven pom.xml depend on dubbo 2.6.3 2. use curator-framework v2.12.0 as zookeeper client 3. startup tomcat 4. shutdown tomcat ### Expected Result tomcat shutdown graceful ### Actual Result tomcat's process was blocked. netty package conflict: > dubbo v2.6.3 depends on netty v3.2.5, > curator-framework v2.12.0 depends on netty v3.7.0. If exclude netty v3.7.0 from curator-framework v2.12.0 in pom.xml, tomcat could been elegant shutdowned. According to the issue #1155, higher version of netty created user threads instead of daemon threads, which name "Hashed wheel timer ". But netty v3.2.5 also created user threads: > "Hashed wheel timer " 213 prio=5 os_prio=0 tid=0x00007f58e007b050 nid=0x513d > waiting on condition [0x00007f58d9d91000] > java.lang.Thread.State: TIMED_WAITING (sleeping) > at java.lang.Thread.sleep(Native Method) > at > org.jboss.netty.util.HashedWheelTimer$Worker.waitForNextTick(HashedWheelTimer.java:503) > at > org.jboss.netty.util.HashedWheelTimer$Worker.run(HashedWheelTimer.java:401) > at > org.jboss.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:108) > at java.lang.Thread.run(Thread.java:748) Dubbo's elegant shutdown works fine with netty v3.2.5, but is bocked by netty v3.7.0. What is going on? [ Full content available at: https://github.com/apache/incubator-dubbo/issues/2334 ] This message was relayed via gitbox.apache.org for [email protected]
