Servlet support compiled on RC1 and 2, but stopped with the release.  Bare bones configure:

./configure --with-servlet=/usr/local/java/jakarta/tomcat/classes/ --with-java=/usr/java/jdk1.2.2/

proceeded by make produces:

Making all in Zend
make[1]: Entering directory `/usr/local/src/php-4.0.0/Zend'
/bin/sh ../libtool --silent --mode=compile c++ -DHAVE_CONFIG_H -I. -I. -I..   -D_REENTRANT -DXML_BYTE_ORDER=12 -I../TSRM -DTHREAD=1  -pthread -c zend-scanner-cc.cc
/bin/sh ../libtool --silent --mode=link c++  -pthread  -o libZend_cc.la   zend-scanner-cc.lo  
/bin/sh ../libtool --silent --mode=compile gcc -DHAVE_CONFIG_H -I. -I. -I..   -D_REENTRANT -DXML_BYTE_ORDER=12 -I../TSRM -DTHREAD=1  -g -O2 -pthread  -Wall -c zend-parser.c
/usr/lib/bison.simple:153: conflicting types for `zendparse'
zend_globals_macros.h:37: previous declaration of `zendparse'
/usr/lib/bison.simple: In function `zendparse':
/usr/lib/bison.simple:219: number of arguments doesn't match prototype
/usr/lib/bison.simple:153: prototype declaration
make[1]: *** [zend-parser.lo] Error 1
make[1]: Leaving directory `/usr/local/src/php-4.0.0/Zend'
make: *** [all-recursive] Error 1

Stats:
RedHat 6.2 with Apache 1.3.12 compiled from source
Tomcat 3.1 compiled from source
Blackdown JDK 1.2.2 RC3