`_JAVA_OPTIONS` and `JAVA_TOOL_OPTIONS` environment variable are interpreted by the VM, not the launcher, hence no @-files or launcher-only options. The former is undocumented and unsupported but widely used; the latter is documented and supported.
In JDK 9, javac adds a new `_JAVAC_OPTIONS` environment variable whose name was chosen to match `_JAVA_OPTIONS` but their semantics are not consistent (e.g. prepend vs append).
There is no equivalent environment variable support in the `java` launcher.
This proposes to introduce a new launcher enviornment variable `JAVA_OPTIONS` that is read by the java launcher. It will support multiple @files. Its content will be prepended to the actual command line; consistent with the current javac environment variable. Other JDK command-line tools will follow this general pattern `<TOOL>_OPTIONS`, if a tool-specific environment variable is supported.