diff --git a/cs656/lab4/Makefile b/cs656/lab4/Makefile
index c521ebd..d1abcd8 100644
--- a/cs656/lab4/Makefile
+++ b/cs656/lab4/Makefile
@@ -1,6 +1,8 @@
 
 RESTLET_DIR := $(HOME)/restlet/lib
-RESTLET_JARS := $(subst " ",":",$(shell find $(RESTLET_DIR) -iname '*.jar'))
+nullstring :=
+space := $(nullstring) #
+RESTLET_JARS := $(subst $(space),:,$(shell find $(RESTLET_DIR) -iname '*.jar'))
 export CLASSPATH += $(RESTLET_JARS)
 
 all: