The Diagnostics Collector gathers the Java™ diagnostics files for a problem event.
The Java runtime produces multiple diagnostics files in response to events such as General Protection Faults, out of memory conditions or receiving unexpected operating system signals. The Diagnostics Collector runs just after the Java runtime produces diagnostics files. It searches for system dumps, Java dumps, heap dumps, Java trace dumps and the verbose GC log that match the time stamp for the problem event. If a system dump is found, then optionally the Diagnostics Collector can execute jextract to post-process the dump and capture extra information required to analyze system dumps. The Diagnostics Collector then produces a single .zip file containing all the diagnostics for the problem event. Steps in the collection of diagnostics are logged in a text file. At the end of the collection process, the log file is copied into the output .zip file.
The Diagnostics Collector also has a feature to give warnings if there are JVM settings in place that could prevent the JVM from producing diagnostics. These warnings are produced at JVM start up so that the JVM can be restarted with fixed settings if necessary. The warnings are printed on stderr and in the Diagnostics Collector log file. Fix the settings identified by any warning messages before restarting your Java application. Fixing warnings makes it more likely that the right data is available for IBM® Support to diagnose a Java problem.