How to read the Garbage Collector output (for Sun JVM)
- *-XX:+PrintGCTimeStamps* will print a time stamp before each collection line.
- *-XX:+PrintGCDetails *will print more details at garbage collection. h3. Minor Garbage Collection: As per the description provided by Sun, the minor collection output created by parameters *-verbosegc -XX:+PrintGCDetails *looks like:
*+[GC [ secs]+*
Let’s see a more real example:
*GC* indicates that this is a minor garbage collector. If the executed collection is a global one, then we will see *FullGC* instead of GC.
*DefNew:* This is the *collector type *used for the minor collection. The most common values here are DefNew and ParNew. This depends again on the parameters we set for the JVM, for example *-XX:+UseParNewGC *(for the Parallel New garbage collector).
*960K:* This value is the maximum young area available (Eden + one of the survivor areas). *0.004494 secs: T*his is the pause time for the minor collection. *890K: *This is the occupancy of the entire heap before GC.
*0.004606 secs: *Pause time for the entire garbage collection. h3. Full Garbage Collection: As we have alredy mentioned, when a full garbage collection takes place, the tag *Full GC *appears in the GC output, as you can see in the following example: