Seen in a JPRT test run on windows 32-bit:

command: main -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:. -Xms200M -XX:G1HeapRegionSize=32M gc.g1.humongousObjects.TestHumongousThreshold
reason: User specified action: run main/othervm -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:. -Xms200M -XX:G1HeapRegionSize=32M gc.g1.humongousObjects.TestHumongousThreshold
Mode: othervm [/othervm specified]
Additional options from @modules: --add-modules java.base,java.management --add-exports java.base/jdk.internal.misc=ALL-UNNAMED
elapsed time (seconds): 4.632
configuration:
Boot Layer
  add modules: java.base java.management
  add exports: java.base/jdk.internal.misc ALL-UNNAMED

STDOUT:
gc.g1.humongousObjects.TestHumongousThreshold started
Actual G1 region size 33554432
byte[] memory overhead 12
Doing non-humongous allocations
Testing allocations with byte[] with length from 0 to 129
Testing allocations with byte[] with length from 0 to 16777200 with step 1677720
Testing allocations with byte[] of maximum non-humongous length 16777204
Doing humongous allocations
Testing with byte[] of minimum humongous object 16777205
Testing allocations with byte[] with length from 16777205 to 16777334
Checking that large (more than a half of region size) objects are humongous
STDERR:
java.lang.OutOfMemoryError: Java heap space
at gc.g1.humongousObjects.TestHumongousThreshold.allocateAndCheck(TestHumongousThreshold.java:86)
at gc.g1.humongousObjects.TestHumongousThreshold.main(TestHumongousThreshold.java:160)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:115)
at java.base/java.lang.Thread.run(Thread.java:844)