% ./7u4/bin/java -XX:+AlwaysActAsServerClassMachine -XX:+PrintGCDetails -version
java version "1.7.0_04-ea"
Java(TM) SE Runtime Environment (build 1.7.0_04-ea-b10)
Java HotSpot(TM) Server VM (build 23.0-b12, mixed mode)
Heap
 PSYoungGen      total 21504K, used 737K [0xe4400000, 0xe5c00000, 0xf9c00000)
  eden space 18432K, 4% used [0xe4400000,0xe44b85f8,0xe5600000)
  from space 3072K, 0% used [0xe5900000,0xe5900000,0xe5c00000)
  to   space 3072K, 0% used [0xe5600000,0xe5600000,0xe5900000)
 PSOldGen        total 40960K, used 0K [0xb9c00000, 0xbc400000, 0xe4400000)
  object space 40960K, 0% used [0xb9c00000,0xb9c00000,0xbc400000)
 PSPermGen       total 16384K, used 1367K [0xb5c00000, 0xb6c00000, 0xb9c00000)
  object space 16384K, 8% used [0xb5c00000,0xb5d55e98,0xb6c00000)

% mv 7u4 7u4client
% ./7u4client/bin/java -XX:+AlwaysActAsServerClassMachine -XX:+PrintGCDetails -version
java version "1.7.0_04-ea"
Java(TM) SE Runtime Environment (build 1.7.0_04-ea-b10)
Java HotSpot(TM) Server VM (build 23.0-b12, mixed mode)
Heap
 def new generation   total 19648K, used 699K [0xb5c00000, 0xb7150000, 0xcb150000)
  eden space 17472K,   4% used [0xb5c00000, 0xb5caec58, 0xb6d10000)
  from space 2176K,   0% used [0xb6d10000, 0xb6d10000, 0xb6f30000)
  to   space 2176K,   0% used [0xb6f30000, 0xb6f30000, 0xb7150000)
 tenured generation   total 43712K, used 0K [0xcb150000, 0xcdc00000, 0xf5c00000)
   the space 43712K,   0% used [0xcb150000, 0xcb150000, 0xcb150200, 0xcdc00000)
 compacting perm gen  total 16384K, used 1367K [0xf5c00000, 0xf6c00000, 0xf9c00000)
   the space 16384K,   8% used [0xf5c00000, 0xf5d55e98, 0xf5d56000, 0xf6c00000)
No shared spaces configured.