diff --git a/server/src/main/java/org/elasticsearch/index/query/functionscore/DecayFunctionBuilder.java b/server/src/main/java/org/elasticsearch/index/query/functionscore/DecayFunctionBuilder.java
index 7bca4ac920683..e31e646200a69 100644
--- a/server/src/main/java/org/elasticsearch/index/query/functionscore/DecayFunctionBuilder.java
+++ b/server/src/main/java/org/elasticsearch/index/query/functionscore/DecayFunctionBuilder.java
@@ -65,8 +65,8 @@ public abstract class DecayFunctionBuilder<DFB extends DecayFunctionBuilder<DFB>
     protected static final String DECAY = "decay";
     protected static final String OFFSET = "offset";
 
-    public static double DEFAULT_DECAY = 0.5;
-    public static MultiValueMode DEFAULT_MULTI_VALUE_MODE = MultiValueMode.MIN;
+    public static final double DEFAULT_DECAY = 0.5;
+    public static final MultiValueMode DEFAULT_MULTI_VALUE_MODE = MultiValueMode.MIN;
 
     private final String fieldName;
     //parsing of origin, scale, offset and decay depends on the field type, delayed to the data node that has the mapping for it