The issue was reproduced also on 1.6.0_25, on T1000 and T5440 machines
Java heap size increases after a few days.
Java flags: -DSHVER=1.3,100 -verbose:gc -XX:-ReduceInitialCardMarks -Xms512m -Xmx512m -Dos.heap.max=512m -DREGISTRY_PATH=./registry -DREGISTRY_DEBUG=false

Attached:
jmap1.txt & pmap1.txt were taken on same time - jmap shows 1GB Java heap
jmap2.txt & pmap2.txt show 512m Java heap, but overall process memory is > 2GB.
In both above cases, MaxNewSize==4GB (?!)

Also attached: 'pmap -x' output and 'jinfo -flags' output

> java -version
java version "1.6.0_21"
Java(TM) SE Runtime Environment (build 1.6.0_21-b06)
Java HotSpot(TM) Server VM (build 17.0-b16, mixed mode)

> cat /etc/release
                      Solaris 10 10/09 s10s_u8wos_08a SPARC
           Copyright 2009 Sun Microsystems, Inc. All Rights Reserved.
                        Use is subject to license terms.
                           Assembled 16 September 2009