diff --git a/agrona/src/main/java/org/agrona/collections/Int2NullableObjectHashMap.java b/agrona/src/main/java/org/agrona/collections/Int2NullableObjectHashMap.java
index 826884c05..60602856e 100644
--- a/agrona/src/main/java/org/agrona/collections/Int2NullableObjectHashMap.java
+++ b/agrona/src/main/java/org/agrona/collections/Int2NullableObjectHashMap.java
@@ -29,8 +29,7 @@ public Int2NullableObjectHashMap()
     }
 
     public Int2NullableObjectHashMap(
-        @DoNotSub final int initialCapacity,
-        final float loadFactor)
+        @DoNotSub final int initialCapacity, final float loadFactor)
     {
         super(initialCapacity, loadFactor);
     }
@@ -42,9 +41,7 @@ public Int2NullableObjectHashMap(
      * @param shouldAvoidAllocation should allocation be avoided by caching iterators and map entries.
      */
     public Int2NullableObjectHashMap(
-        @DoNotSub final int initialCapacity,
-        final float loadFactor,
-        final boolean shouldAvoidAllocation)
+        @DoNotSub final int initialCapacity, final float loadFactor, final boolean shouldAvoidAllocation)
     {
         super(initialCapacity, loadFactor, shouldAvoidAllocation);
     }
@@ -59,13 +56,12 @@ public Int2NullableObjectHashMap(final Int2ObjectHashMap<V> mapToCopy)
         super(mapToCopy);
     }
 
-    @Override
     protected Object mapNullValue(final Object value)
     {
         return value == null ? NullReference.INSTANCE : value;
     }
 
-    @Override
+    @SuppressWarnings("unchecked")
     protected V unmapNullValue(final Object value)
     {
         return value == NullReference.INSTANCE ? null : (V)value;
diff --git a/agrona/src/main/java/org/agrona/collections/Int2ObjectHashMap.java b/agrona/src/main/java/org/agrona/collections/Int2ObjectHashMap.java
index 2461c67a3..42c30fc24 100644
--- a/agrona/src/main/java/org/agrona/collections/Int2ObjectHashMap.java
+++ b/agrona/src/main/java/org/agrona/collections/Int2ObjectHashMap.java
@@ -289,7 +289,7 @@ public V put(final Integer key, final V value)
     public V put(final int key, final V value)
     {
         final V val = (V)mapNullValue(value);
-        requireNonNull(val, "Value cannot be null");
+        requireNonNull(val, "value cannot be null");
 
         V oldValue = null;
         @DoNotSub final int mask = values.length - 1;
@@ -520,6 +520,7 @@ protected Object mapNullValue(final Object value)
         return value;
     }
 
+    @SuppressWarnings("unchecked")
     protected V unmapNullValue(final Object value)
     {
         return (V)value;
@@ -570,7 +571,7 @@ private void increaseCapacity()
         @DoNotSub final int newCapacity = values.length << 1;
         if (newCapacity < 0)
         {
-            throw new IllegalStateException("Max capacity reached at size=" + size);
+            throw new IllegalStateException("max capacity reached at size=" + size);
         }
 
         rehash(newCapacity);
@@ -756,7 +757,7 @@ public void clear()
         public boolean contains(final Object o)
         {
             final Entry entry = (Entry)o;
-            final int key = ((Integer)entry.getKey()).intValue();
+            final int key = (Integer)entry.getKey();
             final V value = getMapped(key);
             return value != null && value.equals(mapNullValue(entry.getValue()));
         }
@@ -965,7 +966,7 @@ public V getValue()
         public V setValue(final V value)
         {
             final V val = (V)mapNullValue(value);
-            requireNonNull(val, "Value cannot be null");
+            requireNonNull(val, "value cannot be null");
 
             if (!this.isPositionValid)
             {
diff --git a/agrona/src/main/java/org/agrona/collections/Object2NullableObjectHashMap.java b/agrona/src/main/java/org/agrona/collections/Object2NullableObjectHashMap.java
index f6cc98208..c33335565 100644
--- a/agrona/src/main/java/org/agrona/collections/Object2NullableObjectHashMap.java
+++ b/agrona/src/main/java/org/agrona/collections/Object2NullableObjectHashMap.java
@@ -24,9 +24,7 @@ public Object2NullableObjectHashMap()
     {
     }
 
-    public Object2NullableObjectHashMap(
-        final int initialCapacity,
-        final float loadFactor)
+    public Object2NullableObjectHashMap(final int initialCapacity, final float loadFactor)
     {
         super(initialCapacity, loadFactor);
     }
@@ -37,20 +35,17 @@ public Object2NullableObjectHashMap(
      * @param shouldAvoidAllocation should allocation be avoided by caching iterators and map entries.
      */
     public Object2NullableObjectHashMap(
-        final int initialCapacity,
-        final float loadFactor,
-        final boolean shouldAvoidAllocation)
+        final int initialCapacity, final float loadFactor, final boolean shouldAvoidAllocation)
     {
         super(initialCapacity, loadFactor, shouldAvoidAllocation);
     }
 
-    @Override
     protected Object mapNullValue(final Object value)
     {
         return value == null ? NullReference.INSTANCE : value;
     }
 
-    @Override
+    @SuppressWarnings("unchecked")
     protected V unmapNullValue(final Object value)
     {
         return value == NullReference.INSTANCE ? null : (V)value;
diff --git a/agrona/src/main/java/org/agrona/collections/Object2ObjectHashMap.java b/agrona/src/main/java/org/agrona/collections/Object2ObjectHashMap.java
index 3049d5f29..8293b0063 100644
--- a/agrona/src/main/java/org/agrona/collections/Object2ObjectHashMap.java
+++ b/agrona/src/main/java/org/agrona/collections/Object2ObjectHashMap.java
@@ -474,6 +474,7 @@ protected Object mapNullValue(final Object value)
         return value;
     }
 
+    @SuppressWarnings("unchecked")
     protected V unmapNullValue(final Object value)
     {
         return (V)value;
diff --git a/agrona/src/test/java/org/agrona/collections/Int2ObjectHashMapTest.java b/agrona/src/test/java/org/agrona/collections/Int2ObjectHashMapTest.java
index 1b6c76ea9..e26514a71 100644
--- a/agrona/src/test/java/org/agrona/collections/Int2ObjectHashMapTest.java
+++ b/agrona/src/test/java/org/agrona/collections/Int2ObjectHashMapTest.java
@@ -223,6 +223,7 @@ public void shouldIterateValues()
 
         for (final String s : intToObjectMap.values())
         {
+            //noinspection UseBulkOperation
             copyToSet.add(s);
         }
 
@@ -273,6 +274,7 @@ private void assertIterateKeys(final Collection<Integer> initialSet)
         final Collection<Integer> copyToSet = new HashSet<>();
         for (final Integer aInteger : intToObjectMap.keySet())
         {
+            //noinspection UseBulkOperation
             copyToSet.add(aInteger);
         }
 
@@ -385,13 +387,11 @@ public void shouldAllowNullValuesWithNullMapping()
         {
             private final Object nullRef = new Object();
 
-            @Override
             protected Object mapNullValue(final Object value)
             {
                 return value == null ? nullRef : value;
             }
 
-            @Override
             protected String unmapNullValue(final Object value)
             {
                 return value == nullRef ? null : (String)value;