I also ran into this SHA MessageDigest issue. You need $WAS_HOME/java/jre/lib/ext in -Djava.ext.dirs, along with everything else.

export JAVA_EXT_DIRS=$WAS_HOME/java/jre/lib/ext:$WAS_HOME/lib:$WAS_HOME/plugins:$WAS_HOME/classes

Then use it in java command line. -Djava.ext.dirs=$JAVA_EXT_DIRS