Troubleshooting tips
If you are experiencing problems, read this list of common issues and solutions.
Data items unavailable
Data items that represent
types of data, for example are unavailable
in the following situations:
- If this information is not present in the log file that you opened. For example, Nursery size is unavailable when you open a verbose garbage collection log from a runtime environment that is running with a garbage collection policy that is not gencon. Similarly, Concurrent Trace Kickoff items are unavailable if the policy is not optavgpause.
- When you change the limits in the Axes view, you restrict the data that is used to generate information in the report and to populate the menu items. Some menu items might therefore become unavailable. Reset the axes to restore the limits to their default values and re-enable the menu items. If the Line plot is not plotting any data, the Reset button resets the limits for all units.
False Java VM restarts
You can open a compressed file that contains a sequence of files generated by using the -Xverbosegclog:filename,number_of_files,number_of_gc_cycles Java™ parameter. If you then select JVM restarts from the VGC category in the Data selector view, the start of each file is marked as a Java VM restart, even though the Java VM did not actually restart at that point. This behavior is due to the way in which Java VM restarts are detected. Uncheck JVM restarts if you find the results confusing. To identify genuine Java VM restarts, look for corresponding sudden drops in categories such as heap size and used heap.