lib/scripts/getsettings

   export JAVA_HOME="$ISABELLE_JDK_HOME/jre"
 else
   export JAVA_HOME="$ISABELLE_JDK_HOME"
 fi
 
-ISABELLE_SETUP_CLASSPATH="$(isabelle_java java -jar "$(platform_path "$ISABELLE_SETUP_JAR")" classpath)"
+if [ -e "$ISABELLE_SETUP_JAR" ]; then
+  ISABELLE_SETUP_CLASSPATH="$(isabelle_java java -jar "$(platform_path "$ISABELLE_SETUP_JAR")" classpath)"
+fi
 
 set +o allexport
 
 fi