When the attached test case is run on Classic VM (build JDK-1.2fcs-O, green threads, sunwjit) with Xmaxf parameter of 0.6, 98% of the heap is free at conclusion of test case after gc is called, rather than approximately 60%, as requested.

Verbosegc output at conclusion of test case run shows that 98% of
the heap is free and that the last free block is only 872.

GC pass4 1: Total memory is: 11100152
<GC: compactHeap took 2 ms, swap time = 2 ms, blocks_moved=11>
<GC: 0 explicitly pinned objects, 6 conservatively pinned objects>
<GC: last free block at 0xec71fc94 of length 872>
                                       ^^^^^^^^^
<GC: last free block is at end>
<GC: freed 13 objects, 1032 bytes in 9 ms, 98% free (10642904/10833096)>
                                           ^^^^^
  <GC: init&scan: 1 ms, scan handles: 4 ms, sweep: 1 ms, compact: 3 ms>
  <GC: 0 register-marked objects, 12 stack-marked objects>
  <GC: 0 register-marked handles, 90 stack-marked handles>
  <GC: refs: soft 0 (age >= 32), weak 0, final 0, phantom 0>
GC pass5 1: Total memory is: 11100152
==================================
After sleep
----------------------------------
Total memory is: 11100152
Free memory is: 10898432
==================================

Test case parameter:
-verbosegc -Xmx64m -Xmaxf0.6 -Xminf0.1 -Xmine5000 HeapTest 10 3