For the latest jdk1.4 build (b50) on Solaris/sparc, I got a warning message from
running client mode. There is no such warning from early builds and server
mode for b50 works fine without the warning.

You would need to set the CLASSPATH environment as the following
to repeat:

% uname -a
SunOS vispro 5.7 Generic_106541-11 sun4u sparc SUNW,Ultra-30

% setenv JSDK /usr/local/java/jsdk3.0/solaris

% setenv CLASSPATH $JSDK/lib/jsdk.jar:$JSDK/lib/servlet.jar:.

% /usr/local/java/jdk1.4/solsparc/bin/java -version

Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-beta-b50)
Java HotSpot(TM) Client VM (build 1.4beta-B50, mixed mode)Java HotSpot(TM) Client VM warning: ValueGen::do_LoopEnter(...) not implemented yet
Java HotSpot(TM) Client VM warning: ValueGen::do_LoopExit(...) not implemented yet