do not cache as java can turn on at any time

Author: scivision

+stdlib/has_java.m

@@ -1,15 +1,9 @@
 %% HAS_JAVA detect if JVM is available
 % requires: java
 
-function ok = has_java()
+function y = has_java()
 
-persistent h;
-
-if isempty(h)
-  h = usejava('jvm');
-end
-
-ok = h;
+y = usejava('jvm');
 
 end