diff --git a/rskj-core/src/main/java/org/ethereum/rpc/parameters/HexAddressParam.java b/rskj-core/src/main/java/org/ethereum/rpc/parameters/HexAddressParam.java
index a8c939cc7e5..863a682018c 100644
--- a/rskj-core/src/main/java/org/ethereum/rpc/parameters/HexAddressParam.java
+++ b/rskj-core/src/main/java/org/ethereum/rpc/parameters/HexAddressParam.java
@@ -49,6 +49,11 @@ public RskAddress getAddress() {
         return address;
     }
 
+    @Override
+    public String toString() {
+        return address.toString();
+    }
+    
     public static class Deserializer extends StdDeserializer<HexAddressParam> {
         private static final long serialVersionUID = 1L;
 
diff --git a/rskj-core/src/main/java/org/ethereum/rpc/parameters/HexNumberParam.java b/rskj-core/src/main/java/org/ethereum/rpc/parameters/HexNumberParam.java
index aca8eeb28ef..bbb3539fdd7 100644
--- a/rskj-core/src/main/java/org/ethereum/rpc/parameters/HexNumberParam.java
+++ b/rskj-core/src/main/java/org/ethereum/rpc/parameters/HexNumberParam.java
@@ -51,6 +51,11 @@ public String getHexNumber() {
         return this.hexNumber;
     }
 
+    @Override
+    public String toString() {
+        return this.hexNumber;
+    }
+
     public static class Deserializer extends StdDeserializer<HexNumberParam> {
         private static final long serialVersionUID = 1L;