There's a little documentation bug in Java's build-in help.
You can see this bug while running "java -Xrunhprof:help"

% java -Xrunhprof:help
Hprof usage: -Xrunhprof[:help]|[<option>=<value>, ...]

Option Name and Value Description Default
--------------------- ---------------------- -------
heap=dump|sites|all heap profiling all
cpu=samples|times|old CPU usage off
monitor=y|n monitor contention n
format=a|b ascii or binary output a
file=<file> write data to file java.hprof(.txt for ascii)
net=<host>:<port> send data over a socket write to file
depth=<size> stack trace depth 4
cutoff=<value> output cutoff point 0.0001
lineno=y|n line number in traces? y
thread=y|n thread in traces? n
doe=y|n dump on exit? y

Example: java -Xrunhprof:cpu=samples,file=log.txt,depth=3 FooClass
---
In Java 1.2.2_11 the first line is
Hprof usage: -Xrunhprof[:help]|[:<option>=<value>, ...]

In Java 1.3.1_04, 1.4.0_01 and 1.4.1_beta (b14) the first line is
Hprof usage: -Xrunhprof[:help]|[<option>=<value>, ...]

Due to the fact that options must have a leading colon, the first line should be
Hprof usage: -Xrunhprof:[help]|[<option>=<value>, ...]
or at least sound like the line from 1.2.2:
Hprof usage: -Xrunhprof[:help]|[:<option>=<value>, ...]

Please note, that doc is correct in 1.3.x and 1.4.x if you're running
% java -X | grep runhprof
    -Xrunhprof[:help]|[:<option>=<value>, ...]