This page is of interest to users of versions of the Java SDK on Solaris older than 1.3.0.

Prior to version 1.3.0, the production releases of the Java 2 SDK for Solaris shipped with a virtual-machine implementation known as the Exact VM (EVM). Beginning with version 1.3.0, the Exact VM was replaced by the Java HotSpot VM.

Java HotSpot VM Equivalents of Exact VM Options

Some options supported by the Exact VM have changed names or become obsolete in the Java HotSpot VM. These EVM options and their Java HotSpot VM equivalents are given in the following table.

 

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EVM Option	Description	Java HotSpot equivalent
-Xt	Instruction tracing	None (obsolete option)
-Xtm	Method tracing	None (obsolete option)
-Xoss	Maximum java stack size	None (HotSpot doesn't have separate native and Java stacks)
-Xverifyheap	Verify heap integrity	-XX:+VerifyBeforeGC -XX:+VerifyAfterGC -XX:+VerifyTLE (-XX:+VerifyTLAB in J2SE 1.4) -XX:+VerifyBeforeScavenge -XX:+VerifyAfterScavenge (all debug only)
-Xmaxjitcodesize	Maximum Comiled code size	-Xmaxjitcodesize<num> (used to be -Xmaxjitcodesize=32m, now -Xmaxjitcodesize32m)
-Xoptimize	Use optimizing JIT Compiler	-server
-Xconcgc	Use concurrent garbage collector (1.2.2_07+)	-XX:+UseConcMarkSweepGC (available beginning with J2SE 1.4.1)

 

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The Java HotSpot VM currently recognizes the following -X options that were not supported by the Exact VM.

Option	Description
-Xincgc	Use Train GC
-Xnoincgc	Do not use Train Garbage Collection (default)
-XX:MaxHeapFreeRatio=<Maximum>	heap free percentage (default 70)
-XX:MinHeapFreeRatio=<Minimum>	heap free percentage (default 40)
-Xint	Intepreter only (no JIT Compilation)
-XX:+UseBoundThreads	Bind user level threads (Solaris only)
-Xmn<Size>	Set the size of the young generation (available beginning in J2SE 1.4.0)
-XX:+UseParallelGC	Use parallel garbage collection (available beginning in J2SE 1.4.1)
-XX:+UseAltSigs	On the Solaris operating environment, the VM uses SIGUSR1 by default, which can sometimes conflict with applications that signal-chain SIGUSR1. -XX:+UseAltSigs will cause the VM to use signals other than SIGUSR1 and SIGUSR2 as the default. Available beginning in J2SE 1.4.1 on the Solaris operating environment.

 

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Java HotSpot VM Equivalents to _JIT_ARGS Environment Variables
Most _JIT_ARGS environment variables are internal debugging options only and have no corresponding Java HotSpot options. Most simply turn off some form of optimization which may have caused instability when first introduced and could be used by the internal testing group to track down problems.

_JIT_ARGS Environment	HotSpot Option	Description
jit/jbe	-client/-server	jbe is the same as -Xoptimize in 1.2 based systems, jit is the default. Use -server in 1.3 to replace -Xoptimize (or jbe) in 1.2.
trace	-XX:+PrintCompilation	traces methods as compiled
V8/V9	-XX:+UseV8InstrsOnly	Done autmatically on both systems, force architecture using these flags (Sparc/debug only)

 

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Java HotSpot VM Equivalents _JVM_ARGS Environment Variables

_JVM_ARGS Environment	HotSpot Option	Description
bound_threads	-XX:+UseBoundThreads	This option forces all threads to be created as bound threads.
fixed_size_young_gen	-XX:NewSize=<size> -XX:MaxNewSize=<size> for 1.3 -Xmn<size> for 1.4	Disable young generation resizing. To do this on HotSpot, simply set the size of the young generation to a constant.
gc_stats	-verbose:gc	Turns on various forms of gc statistics gathering.
ims_concurrent	none
inline_instrs	-XX:MaxInlineSize=<size>	Integer specifying maximum number of bytecode instructions in a method which gets inlined.
	-XX:FreqInlineSize=<size>	Integer specifying maximum number of bytecode instructions in a frequently executed method which gets inlined.
inline_print	-XX:+PrintInlining	Print message about inlined methods (debug only)
no_parallel_gc	none
sync_final	none
yield_interval	-XX:DontYieldALotInterval=<ms>	(debug only) Interval in milliseconds between yields.
monitor_order	none