-Xbatch       disable background compilation
    -Xbootclasspath/a:<bootstrap class path>
                  A : separated list of directories, JAR archives,
                  and ZIP archives, append to end of bootstrap class path
    -Xcheck:jni   perform additional checks for JNI functions
    -Xcomp        forces compilation of methods on first invocation
    -Xdebug       provided for backward compatibility
    -Xdiag        show additional diagnostic messages
    -Xfuture      enable strictest checks, anticipating future default
    -Xint         interpreted mode execution only
    -Xinternalversion
                  displays more detailed JVM version information than the
                  -version option
    -Xloggc <file>
                  log GC status to a file with time stamps
    -Xmixed       mixed mode execution (default)
    -Xmn<size>    sets the initial and maximum size (in bytes) of the heap
                                        for the young generation (nursery)
    -Xms<size>    set initial Java heap size
    -Xmx<size>    set maximum Java heap size
    -Xnoclassgc   disable class garbage collection
    -Xprof        output cpu profiling data (deprecated)
    -Xrs          reduce use of OS signals by Java/VM (see documentation)
    -Xshare:[auto | off | on ]
                  auto: use shared class data if possible (default)
                  off:  do not attempt to use shared class data
                  on:   require using shared class data, otherwise fail.       
    -XshowSettings
                  show all settings and continue
    -XshowSettings:[all | local | properties | vm]
                  all: show all settings and continue
                  locale: show all locale related settings and continue 
                  properties: show all property settings and continue
                  vm: show all vm related settings and continue
    -Xss<size>    set java thread stack size
    -Xverify      sets the mode of the byte-code verifier
    --add-reads <module>=<target-module>(,<target-module>)*
                  updates <module> to read <target-module>, regardless
                  of module declaration. 
                  <target-module> can be ALL-UNNAMED to read all unnamed
                  modules.
    --add-exports <module>/<package>=<target-module>(,<target-module>)*
                  updates <module> to export <package> to <target-module>,
                  regardless of module declaration.
                  <target-module> can be ALL-UNNAMED to export to all
                  unnamed modules.
    --add-opens <module>/<package>=<target-module>(,<target-module>)*
                  updates <module> to open <package> to
                  <target-module>, regardless of module declaration.
    --illegal-access=<value>
                  permit or deny access to members of types in named modules
                  by code in unnamed modules.
                  <value> is one of "deny", "permit", "warn", or "debug"
                  This option will be removed in a future release.
    --limit-modules <module name>[,<module name>...]
                  limit the universe of observable modules
    --patch-module <module>=<file>(:<file>)*
                  override or augment a module with classes and resources
                  in JAR files or directories.
    --disable-@files
                  disable further argument file expansion

These extra options are subject to change without notice.