![]() Previous |
![]() Next |
The Lock Instances tab contains information about the lock instance events in the Java application.
For information about using the range navigator, see Using the Range Navigator.
The Lock Instances panel shows a histogram of lock instance events per address. It contains a pie chart that shows the relative lock instance count for each monitor address. Clicking a color on the pie chart highlights the corresponding monitor address in the legend. The pie chart legend contains a table that lists the monitor addresses with lock instances. This table contains the following columns:
Monitor Address: The address of the object synchronized on.
Monitor Class: The class of the object synchronized on.
Count: The number of lock instance events for the address.
Total Duration: The total duration of lock instance events for the address.
For information about working with tables, see Working with Tables.
When you select a monitor address in the Lock Instances table, the corresponding stack trace for the selected monitor is displayed in the Trace Tree panel, and the threads that are blocking on the selected monitor are displayed in the Top Threads panel. Each of the two panels contains a table with either the stack trace or blocking threads, and the number of relevant lock instances.
At the bottom of the Lock Instances tab, the Garbage Collections panel displays the garbage collection (GC) events that occurred during the time of recording. This is done because a GC event can move the lock instance to a new address, and JFR will consider it to be a different lock instance. To make sure that you do not get multiple representations of the same lock instance, select the time range between consecutive GC events. This will line up the range navigator accordingly and you will be sure that there are no duplicate lock instances.