We recently had a situation where a production machine went down with a massive thread dump. It's resin webserver, and it gave 'Full thread dump Java HotSpot(TM) 64-Bit Server VM (14.0-b16 mixed mode):'.
There are a ton of BLOCKED threads, but they are confusing to me. IE, one is like:
"resin-8576" daemon prio=10 tid=0x00007f871827b800 nid=0x6b5 waiting for monitor entry [0x00007f864a7e6000]
java.lang.Thread.State: BLOCKED (on object monitor)
at java.lang.String.toCharArray(String.java:2725)
at java.lang.Thread.setName(Thread.java:1051)
at com.caucho.server.port.TcpConnection.run(TcpConnection.java:605)
at com.caucho.util.ThreadPool$Item.runTasks(ThreadPool.java:730)
at com.caucho.util.ThreadPool$Item.run(ThreadPool.java:649)
at java.lang.Thread.run(Thread.java:619)
The code there is
char result[] = new char[count];
Another one is like
"resin-8574" daemon prio=10 tid=0x00007f8718277800 nid=0x6b3 waiting for monitor entry [0x00007f864a9e8000]
java.lang.Thread.State: BLOCKED (on object monitor)
at java.lang.String.valueOf(String.java:2840)
at java.lang.Thread.getName(Thread.java:1061)
at com.caucho.server.port.TcpConnection.run(TcpConnection.java:603)
at com.caucho.util.ThreadPool$Item.runTasks(ThreadPool.java:730)
at com.caucho.util.ThreadPool$Item.run(ThreadPool.java:649)
at java.lang.Thread.run(Thread.java:619)
Where the code of String there is
return new String(data);
Those seem like strange places to be blocked.
Could anyone suggest a reason those calls would be blocking?
Thanks, -kal