The following heap parameters cause "zero based Compressed Oops" to be used, while "zero based Compressed Oops, 32-bits Oops" are expected. The parameters are "near maximum" for "zero based Compressed Oops, 32-bi
ts Oops" mode, i.e. HeapBaseMinAddress + Xmx + MaxPermSize = 4g:

1.
.../solaris-amd64//bin/java -d64 -server -Xmixed -XX:+UseParallelGC -XX:ObjectAlignmentInBytes=8 -XX:HeapBaseMinAddress=2048m -Xmx1024m -XX:MaxPermSize=1024m -XX:+UnlockDiagnosticVMOptions -XX:+PrintCompressedOop
sMode -version

heap address: 0x0000000080000000, size: 2050 MB, zero based Compressed Oops

2.
.../solaris-amd64//bin/java -d64 -server -Xmixed -XX:+UseParallelGC -XX:ObjectAlignmentInBytes=8 -XX:HeapBaseMinAddress=1536m -Xmx2048m -XX:MaxPermSize=512m -XX:+UnlockDiagnosticVMOptions -XX:+PrintCompressedOopsMode -version

heap address: 0x0000000060000000, size: 2562 MB, zero based Compressed Oops

3.
.../solaris-amd64//bin/java -d64 -server -Xmixed -XX:+UseParallelGC -XX:ObjectAlignmentInBytes=16 -XX:HeapBaseMinAddress=2048m -Xmx1024m -XX:MaxPermSize=1024m -XX:+UnlockDiagnosticVMOptions -XX:+PrintCompressedOopsMode -version

heap address: 0x0000000080000000, size: 2050 MB, zero based Compressed Oops

4.
.../solaris-amd64//bin/java -d64 -server -Xmixed -XX:+UseParallelGC -XX:ObjectAlignmentInBytes=16 -XX:HeapBaseMinAddress=1536m -Xmx2048m -XX:MaxPermSize=512m -XX:+UnlockDiagnosticVMOptions -XX:+PrintCompressedOopsMode -version

heap address: 0x0000000060000000, size: 2562 MB, zero based Compressed Oops



The following heap parameters cause "Compressed Oops with base" to be used, while "zero based Compressed Oops" are expected. The parameters are "near maximum" for "Compressed Oops with base", i.e. HeapBaseMinAddress + Xmx + MaxPermSize = 32g (64g if -XX:ObjectAlignmentInBytes=16):

5.
.../solaris-amd64//bin/java -d64 -server -Xmixed -XX:+UseParallelGC -XX:ObjectAlignmentInBytes=8 -XX:HeapBaseMinAddress=16384m -Xmx8192m -XX:MaxPermSize=8192m -XX:+UnlockDiagnosticVMOptions -XX:+PrintCompressedOopsMode -version

Protected page at the reserved heap base: 0x00000003ffe00000 / 2097152 bytes

heap address: 0x0000000400000000, size: 16386 MB, Compressed Oops with base: 0x00000003fffff000

6.
.../solaris-amd64//bin/java -d64 -server -Xmixed -XX:+UseParallelGC -XX:ObjectAlignmentInBytes=8 -XX:HeapBaseMinAddress=16128m -Xmx8320m -XX:MaxPermSize=8320m -XX:+UnlockDiagnosticVMOptions -XX:+PrintCompressedOopsMode -version

Protected page at the reserved heap base: 0x00000003efe00000 / 2097152 bytes

heap address: 0x00000003f0000000, size: 16642 MB, Compressed Oops with base: 0x00000003effff000

7.
.../solaris-amd64//bin/java -d64 -server -Xmixed -XX:+UseParallelGC -XX:ObjectAlignmentInBytes=16 -XX:HeapBaseMinAddress=65400m -Xmx112m -XX:MaxPermSize=24m -XX:+UnlockDiagnosticVMOptions -XX:+PrintCompressedOopsMode -version

Protected page at the reserved heap base: 0x0000000ff77f0000 / 65536 bytes

heap address: 0x0000000ff7800000, size: 138 MB, Compressed Oops with base: 0x0000000ff77ff000

8.
.../solaris-amd64//bin/java -d64 -server -Xmixed -XX:+UseParallelGC -XX:ObjectAlignmentInBytes=16 -XX:HeapBaseMinAddress=32762m -Xmx16390m -XX:MaxPermSize=16384m -XX:+UnlockDiagnosticVMOptions -XX:+PrintCompressedOopsMode -version

Protected page at the reserved heap base: 0x00000007ff800000 / 2097152 bytes

heap address: 0x00000007ffa00000, size: 32776 MB, Compressed Oops with base: 0x00000007ff9ff000



All instances are common to solaris-sparcv9 and solaris-amd64, UseParallelGC and UseParallelOldGC