diff --git a/rskj-core/src/main/java/org/ethereum/vm/CallCreate.java b/rskj-core/src/main/java/org/ethereum/vm/CallCreate.java
index eb8fd00ded5..78589947a43 100644
--- a/rskj-core/src/main/java/org/ethereum/vm/CallCreate.java
+++ b/rskj-core/src/main/java/org/ethereum/vm/CallCreate.java
@@ -17,7 +17,6 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
-
 package org.ethereum.vm;
 
 import co.rsk.core.types.bytes.BytesSlice;
@@ -28,11 +27,10 @@
  */
 public class CallCreate {
 
-    final BytesSlice data;
-    final byte[] destination;
-    final long gasLimit;
-    final byte[] value;
-
+    private final BytesSlice data;
+    private final byte[] destination;
+    private final long gasLimit;
+    private final byte[] value;
 
     public CallCreate(BytesSlice data, byte[] destination, long gasLimit, byte[] value) {
         this.data = data;
diff --git a/rskj-core/src/main/java/org/ethereum/vm/program/Memory.java b/rskj-core/src/main/java/org/ethereum/vm/program/Memory.java
index 72ed443cb2f..ea4c62907d1 100644
--- a/rskj-core/src/main/java/org/ethereum/vm/program/Memory.java
+++ b/rskj-core/src/main/java/org/ethereum/vm/program/Memory.java
@@ -38,7 +38,7 @@ public class Memory implements ProgramListenerAware {
     private static final int CHUNK_SIZE = 1024;
     private static final int WORD_SIZE = 32;
 
-    private List<byte[]> chunks = new LinkedList<>();
+    private final List<byte[]> chunks = new LinkedList<>();
     private int softSize;
     private ProgramListener traceListener;
 
diff --git a/rskj-core/src/main/java/org/ethereum/vm/program/invoke/ProgramInvokeImpl.java b/rskj-core/src/main/java/org/ethereum/vm/program/invoke/ProgramInvokeImpl.java
index 41a565a8f71..aa46d259ffa 100644
--- a/rskj-core/src/main/java/org/ethereum/vm/program/invoke/ProgramInvokeImpl.java
+++ b/rskj-core/src/main/java/org/ethereum/vm/program/invoke/ProgramInvokeImpl.java
@@ -37,7 +37,7 @@
  */
 public class ProgramInvokeImpl implements ProgramInvoke {
 
-    private BlockStore blockStore;
+    private final BlockStore blockStore;
     /**
      * TRANSACTION  env **
      */
@@ -47,9 +47,8 @@ public class ProgramInvokeImpl implements ProgramInvoke {
     private final DataWord balance;
     private final DataWord txGasPrice;
     private final DataWord callValue;
-    private long gas;
-
-    BytesSlice msgData;
+    private final long gas;
+    private final BytesSlice msgData;
 
     /**
      * BLOCK  env **