diff --git a/prism/src/param/Makefile b/prism/src/param/Makefile
index 548f9b5a..99845c91 100644
--- a/prism/src/param/Makefile
+++ b/prism/src/param/Makefile
@@ -12,7 +12,7 @@ PRISM_DIR_REL = ../..
 
 JNI_GEN_HEADER_DIR=$(THIS_DIR)/$(PRISM_DIR_REL)/$(INCLUDE_DIR)/jni
 
-JAVA_FILES = $(wildcard *.java)
+JAVA_FILES_ALL = $(wildcard *.java)
 JAVA_FILES = $(subst package-info.java,,$(JAVA_FILES_ALL))
 CLASS_FILES = $(JAVA_FILES:%.java=$(PRISM_DIR_REL)/$(CLASSES_DIR)/$(THIS_DIR)/%.class)