Java threadump value "wait on condition"

Question

I have a threaddump application that showed 3 threads, as shown below.

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"http-443-11" daemon prio=10 tid=0x00000000473bc800 nid=0x3590 waiting on condition [0x0000000061818000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000007612a3880> (a java.util.concurrent.Semaphore$NonfairSync) "http-443-4" daemon prio=10 tid=0x00000000451f6000 nid=0x243a waiting on condition [0x0000000055354000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000007612a3880> (a java.util.concurrent.Semaphore$NonfairSync) "http-443-7" daemon prio=10 tid=0x000000004602e000 nid=0x2974 waiting on condition [0x000000005e6e7000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000007612a3880> (a java.util.concurrent.Semaphore$NonfairSync) 

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What is the meaning of "expectation provided []"? What does the number mean in the []?

Answer 1

In the thread stack, we see that the threads are daemon threads and are waiting for the task to complete. Since these threads are created when the JVM starts, they will not be killed if the JVM does not shut down or no non-daemon threads are started, so they are waiting for tasks. Let's say a garbage collection is a daemon thread that may not work continuously, it may be in a waiting state.