diff -r 1e23caac8757 -r 3c0193f82d20 bin/isabelle_java
--- a/bin/isabelle_java	Mon Oct 03 16:50:29 2016 +0200
+++ b/bin/isabelle_java	Mon Oct 03 17:23:33 2016 +0200
@@ -64,6 +64,7 @@
     echo "Unknown JAVA_HOME -- Java unavailable" >&2
     exit 127
   else
+    unset ISABELLE_HOME
     unset CLASSPATH
     exec "$JAVA_HOME/bin/java" "${JAVA_ARGS[@]}" -classpath "$ISABELLE_CLASSPATH" "$@"
   fi