diff -r 51560e392e1b -r 34fac6fb9b03 lib/Tools/java
--- a/lib/Tools/java	Thu Aug 23 20:49:00 2012 +0200
+++ b/lib/Tools/java	Thu Aug 23 21:23:14 2012 +0200
@@ -5,13 +5,6 @@
 # DESCRIPTION: invoke Java within the Isabelle environment
 
 CLASSPATH="$(jvmpath "$CLASSPATH")"
+isabelle_jdk java -Dfile.encoding=UTF-8 -server \
+  "-Djava.ext.dirs=$(jvmpath "$ISABELLE_JAVA_EXT:$ISABELLE_HOME/lib/classes/ext")" "$@"
 
-if isabelle_jdk java -server >/dev/null 2>/dev/null; then
-  SERVER="-server"
-else
-  SERVER=""
-fi
-
-isabelle_jdk java -Dfile.encoding=UTF-8 $SERVER \
-  "-Djava.ext.dirs=$("$ISABELLE_HOME/src/Tools/JVM/java_ext_dirs")" "$@"
-