Does java garbage collection log entry “Full GC (System)” mean some class called System.gc()?

Question

What does \"Full GC (System)\" entry in the garbage collection logs mean? That some class called System.gc() ?

My garbage collection logs has two different entry typ

Answer 1

I test explicit GC on my mac, it do show "Full GC (System)" when using jdk 1.6, but show "Full GC" with jdk 1.7

So don't rely on the "System" label when you tuning GC log unless you know exactly about running environment and jdk version number