In Solaris 10 the ptools (process tools) were enhanced to display data for specific threads in a process. This functionality can be tapped into by appending a slash and a thread id to the ptool command line:
$ pstack 739/2
739: java TestApp
----------------- lwp# 2 / thread# 2 --------------------
feeb3025 lwp_cond_wait (806eeb8, 806eea0, 0, 0)
feac58c1 __1cHMonitorEwait6Mbl_b_ (806ee48, 0, 0) + 2c1
feb28310 __1cHThreadsKdestroy_vm6F_b_ (0, 0, 806a79c, 0, 10006, febb59c9) + 7c
fe8e2de2 jni_DestroyJavaVM (fec46dc0) + 12a
0805324c JavaMain (8047cb8) + fec
feeae662 _thr_setup (fe650200) + 52
feeae8c0 _lwp_start (fe650200, 0, 0, 0, 0, 0)
This is extremely useful when you need to interrogate a specific thread in a process (e.g., a thread that is consuming 100% of a CPU), or when a process has 100s or 1000s of threads (which is typically the case with Java applications). Nice!