You can find the following description about option "-Xdebug" in section "VM-Specific(Non-Standard)Option" of "Java2 SDK for Solaris Developer's Guide":

Table 4-1. Currently Accepted -X Options
----------------------------------------
-X Lists available options
-Xbootclasspath[/a|/p]:<path> Sets, appends to, or prepends to boot class path
                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Xdebug Sets, appends to, or prepends to boot class path
                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
As above, the two descriptions about both "-Xbootclasspath" and "-Xdebug" are identical sentence.

I think this sentence about "-Xdebug" is wrong.
Because when I ececuted 'java -X' command, it printed usage message as below:

[rie@suzu]java -X
    -Xt turn on instruction tracing
    -Xtm turn on method tracing
    -Xbootclasspath[/a|/p]:<path>
                      set, append to, or prepend to boot class path <-----
    -Xdebug enable remote debugging <--**** Please Look here!!
    -Xnoclassgc disable class garbage collection
    -Xss<size> set maximum native stack size for any thread
    -Xoss<size> set maximum Java stack size for any thread
    -Xms<size> set initial Java heap size
    -Xmx<size> set maximum Java heap size
    -Xrs reduce the use of OS signals
    -Xrunhprof[:help]|[:<option>=<value>, ...]
                      perform heap or cpu profiling
    -Xmaxjitcodesize<size>
                      set the maximum size (in bytes) for the JIT code area
    -Xsqnopause do not pause for user interaction on sigquit
    -Xoptimize Experimental: Spend more time optimizing methods in the JIT (SPARC only)

The -X options are non-standard and subject to change without notice.
                                      
[rieko.suzuki@Japan 1999-11-18]

no writer asigned to cover JTG information
linda.kaplan@eng 2000-01-10