Understanding GC Logs

The first number "33.125" and "100.667" represent the time the GC took place.

[GC and [full GC] at the beginning of the GC log describe the type of pause for this garbage collection, not the new generation GC or the old GC.

[Defnew, [tenured, [PERMZ indicates the area where the GC occurred

The 3324k->152k (3712K) inside the back square brackets means that the memory area has used capacity (the total capacity of that memory area) since the memory area has used capacity->GC before the GC.

Again, 0.0025925.secs represents the time taken by the GC in this memory area.

Understanding GC Logs