On Wed, 18 Feb 2026 16:50:27 GMT, Oli Gillespie <[email protected]> wrote:
>> Flags passed via a settings file (`.hotspotrc`, or `-XX:Flags=my-file`) do >> not have the `-XX:` prefix like they would have if passed as command-line >> args. `JVM_GetVmArguments` then prints these flags also without the prefix, >> along with command-line flags that _are_ prefixed. >> >> However, users of `JVM_GetVmArguments` expect the arguments to be in a >> format that they can pass as command-line args, for example [in CDS >> static_dump](https://github.com/openjdk/jdk/blob/63f00fff921ed4ac0f595a0a013d399700433a2c/src/java.base/share/classes/jdk/internal/misc/CDS.java#L329-L338) >> - CDS static_dump currently *does not work* if the main VM uses flags from >> a settings file. >> >> So, always add the `-XX:` prefix to flags from settings files in >> `JVM_GetVmArguments`. Updated existing test to cover this behaviour. >> >> I looked for existing users of `JVM_GetVmArguments` and they either seem >> like they'll benefit from this change (CDS, JMH via >> `RuntimeMXBean.getInputArguments()`) or they won't care. >> >> **Testing** >> >> * Updated the existing InputArgument test with a case that verifies the new >> behaviour. >> * Confirmed that CDS static_dump and JMH now work on a VM with flags from a >> file. > > Oli Gillespie has updated the pull request incrementally with one additional > commit since the last revision: > > Remove @author tag and update copyright Yes it would make more sense for the list seen by RuntimeMXBean to have the -XX prefix. It is a change in some very long-standing behavior, so yes maybe release note. test/jdk/java/lang/management/RuntimeMXBean/InputArgument.java line 97: > 95: > 96: List<String> options = rm.getInputArguments(); > 97: if (vmOptions == null) { An existing problem in the test, but getInputArguments() says: "returns an empty list if there is no input argument" ...so would be great if we can throw new RuntimeException("Null value from getInputArguments()") or simliar to cause a failure if it gets a null, while we are here. ------------- PR Comment: https://git.openjdk.org/jdk/pull/29793#issuecomment-3971952560 PR Review Comment: https://git.openjdk.org/jdk/pull/29793#discussion_r2863528701
