diff --git a/src/java/org/apache/cassandra/exceptions/ExceptionCode.java b/src/java/org/apache/cassandra/exceptions/ExceptionCode.java
index 2e196c0bf5ee..176695197151 100644
--- a/src/java/org/apache/cassandra/exceptions/ExceptionCode.java
+++ b/src/java/org/apache/cassandra/exceptions/ExceptionCode.java
@@ -61,7 +61,7 @@ public enum ExceptionCode
             valueToCode.put(code.value, code);
     }
 
-    private ExceptionCode(int value)
+    ExceptionCode(int value)
     {
         this.value = value;
     }
diff --git a/src/java/org/apache/cassandra/transport/messages/ErrorMessage.java b/src/java/org/apache/cassandra/transport/messages/ErrorMessage.java
index 82f8bc73ee17..371ac245faac 100644
--- a/src/java/org/apache/cassandra/transport/messages/ErrorMessage.java
+++ b/src/java/org/apache/cassandra/transport/messages/ErrorMessage.java
@@ -18,9 +18,9 @@
 package org.apache.cassandra.transport.messages;
 
 import java.net.InetAddress;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
 
 import io.netty.buffer.ByteBuf;
 import io.netty.handler.codec.CodecException;
@@ -84,30 +84,21 @@ public ErrorMessage decode(ByteBuf body, ProtocolVersion version)
                 case READ_FAILURE:
                     {
                         ConsistencyLevel cl = CBUtil.readConsistencyLevel(body);
-                        int received = body.readInt();
-                        int blockFor = body.readInt();
+                        final int received = body.readInt();
+                        final int blockFor = body.readInt();
                         // The number of failures is also present in protocol v5, but used instead to specify the size of the failure map
-                        int failure = body.readInt();
+                        final int failures = body.readInt();
 
-                        Map<InetAddressAndPort, RequestFailureReason> failureReasonByEndpoint = new ConcurrentHashMap<>();
-                        if (version.isGreaterOrEqualTo(ProtocolVersion.V5))
-                        {
-                            for (int i = 0; i < failure; i++)
-                            {
-                                InetAddress endpoint = CBUtil.readInetAddr(body);
-                                RequestFailureReason failureReason = RequestFailureReason.fromCode(body.readUnsignedShort());
-                                failureReasonByEndpoint.put(InetAddressAndPort.getByAddress(endpoint), failureReason);
-                            }
-                        }
+                        final Map<InetAddressAndPort, RequestFailureReason> failureReasonByEndpoint = failureReasonByEndPoint(body, version, failures);
 
                         if (code == ExceptionCode.WRITE_FAILURE)
                         {
-                            WriteType writeType = Enum.valueOf(WriteType.class, CBUtil.readString(body));
+                            final WriteType writeType = Enum.valueOf(WriteType.class, CBUtil.readString(body));
                             te = new WriteFailureException(cl, received, blockFor, writeType, failureReasonByEndpoint);
                         }
                         else
                         {
-                            byte dataPresent = body.readByte();
+                            final byte dataPresent = body.readByte();
                             te = new ReadFailureException(cl, received, blockFor, dataPresent != 0, failureReasonByEndpoint);
                         }
                     }
@@ -116,14 +107,14 @@ public ErrorMessage decode(ByteBuf body, ProtocolVersion version)
                 case READ_TIMEOUT:
                     {
                         ConsistencyLevel cl = CBUtil.readConsistencyLevel(body);
-                        int received = body.readInt();
-                        int blockFor = body.readInt();
+                        final int received = body.readInt();
+                        final int blockFor = body.readInt();
                         if (code == ExceptionCode.WRITE_TIMEOUT)
                         {
-                            WriteType writeType = Enum.valueOf(WriteType.class, CBUtil.readString(body));
+                            final WriteType writeType = Enum.valueOf(WriteType.class, CBUtil.readString(body));
                             if (version.isGreaterOrEqualTo(ProtocolVersion.V5) && writeType == WriteType.CAS)
                             {
-                                int contentions = body.readShort();
+                                final int contentions = body.readShort();
                                 te = new CasWriteTimeoutException(writeType, cl, received, blockFor, contentions);
                             }
                             else
@@ -133,7 +124,7 @@ public ErrorMessage decode(ByteBuf body, ProtocolVersion version)
                         }
                         else
                         {
-                            byte dataPresent = body.readByte();
+                            final byte dataPresent = body.readByte();
                             te = new ReadTimeoutException(cl, received, blockFor, dataPresent != 0);
                         }
                     }
@@ -336,6 +327,21 @@ public int encodedSize(ErrorMessage msg, ProtocolVersion version)
             }
             return size;
         }
+
+        private Map<InetAddressAndPort, RequestFailureReason> failureReasonByEndPoint(ByteBuf body, ProtocolVersion version, int failures)
+        {
+            final Map<InetAddressAndPort, RequestFailureReason> failureReasons = new HashMap<>();
+            if (version.isGreaterOrEqualTo(ProtocolVersion.V5))
+            {
+                for (int i = 0; i < failures; i++)
+                {
+                    final InetAddress endpoint = CBUtil.readInetAddr(body);
+                    final RequestFailureReason failureReason = RequestFailureReason.fromCode(body.readUnsignedShort());
+                    failureReasons.put(InetAddressAndPort.getByAddress(endpoint), failureReason);
+                }
+            }
+            return failureReasons;
+        }
     };
 
     private static TransportException getBackwardsCompatibleException(ErrorMessage msg, ProtocolVersion version)
@@ -363,12 +369,12 @@ private static TransportException getBackwardsCompatibleException(ErrorMessage m
                 case WRITE_TIMEOUT:
                     if (msg.error instanceof CasWriteTimeoutException)
                     {
-                        CasWriteTimeoutException cwte = (CasWriteTimeoutException) msg.error;
+                        final CasWriteTimeoutException cwte = (CasWriteTimeoutException) msg.error;
                         return new WriteTimeoutException(WriteType.CAS, cwte.consistency, cwte.received, cwte.blockFor);
                     }
                     break;
                 case CAS_WRITE_UNKNOWN:
-                    CasWriteUnknownResultException cwue = (CasWriteUnknownResultException) msg.error;
+                    final CasWriteUnknownResultException cwue = (CasWriteUnknownResultException) msg.error;
                     return new WriteTimeoutException(WriteType.CAS, cwue.consistency, cwue.received, cwue.blockFor);
             }
         }