How to read a verbose:GC output?

Question

70.222: [GC [PSYoungGen: 131072K->15437K(152896K)] 131072K->15509K(502464K), 0.0228420 secs] [Times: user=0.09 sys=0.01, real=0.02 secs]

Answer 1

You can find tutorials on interpreting verbose GC output eg. in:

• verbosegc output tutorial - Java 7
• Heap settings and reading verbose GC output

Looking at verbosegc output tutorial - Java 7, you can see YoungGen space analysis:

UPDATE 03/27/2014: The "Collection time (secs)" is actually a Timestamp showing the when the GC occurred. The Collection times are reported as Times=user=0.45 sys=0.01, real=0.14 secs].

Here, the 262208K->137900K(100428K) means Java Heap before GC-> Java Heap after GC (Total Size of the Java Heap).

And, OldGen space analysis: