compile and make run without errors, php works fine, but the java extension doesn't:
the settings are shown in phpinfo(), extension_loaded ("java") returns 1, but as soon as I try to instatniate a class (e.g. $system = new Java("java.lang.System");) the script halts:

Unable to load Java Library /usr/local/jdk1.2.2/jre/lib/i386/libjava.so

but this is the path where libjava.so is located. libphp_java.so is aparently found. fiddling with path-settings in php.ini does not affect the problem.

php.ini:
[java]
extension_dir=/usr/local/lib
extension=libphp_java.so
java.class.path=/usr/local/lib/php_java.jar

php runs as apache module, with 
./configure --with-apxs=/usr/local/apache/bin/apxs --with-mysql --enable-track-vars --with-java=/usr/local/jdk1.2.2 --with-config-file-path=/usr/local/lib

jdk used is blackdown jdk1.2.2 (jdk-1.2.2-rc4-linux-i386-glibc-2.1.2.tar)