diff --git a/core/bin/elasticsearch.in.sh b/core/bin/elasticsearch.in.sh
index af68857e0eb..9e1c8d9d42e 100644
--- a/core/bin/elasticsearch.in.sh
+++ b/core/bin/elasticsearch.in.sh
@@ -1,6 +1,12 @@
 #!/bin/sh
 
-ES_CLASSPATH="$ES_CLASSPATH:$ES_HOME/lib/${project.build.finalName}.jar:$ES_HOME/lib/*:$ES_HOME/lib/sigar/*"
+CORE_CLASSPATH="$ES_HOME/lib/${project.build.finalName}.jar:$ES_HOME/lib/*:$ES_HOME/lib/sigar/*"
+
+if [ "x$ES_CLASSPATH" = "x" ]; then
+    ES_CLASSPATH="$CORE_CLASSPATH"
+else
+    ES_CLASSPATH="$ES_CLASSPATH:$CORE_CLASSPATH"
+fi
 
 if [ "x$ES_MIN_MEM" = "x" ]; then
     ES_MIN_MEM=${packaging.elasticsearch.heap.min}