Added eager nullability and type checks of values and functions passed to ChronicleMap, if is probable that they won't be passed (and checked) inside contexts, if, say the key is absent in the map

src/main/java/net/openhft/chronicle/map/AbstractChronicleMap.java

@@ -25,6 +25,7 @@ import java.io.Serializable;
 import java.util.*;
 
 import static java.util.Collections.emptyList;
+import static net.openhft.chronicle.map.Objects.requireNonNull;
 
 abstract class AbstractChronicleMap<K, V> extends AbstractMap<K, V>
         implements ChronicleMap<K, V>, Serializable {
@@ -63,6 +64,7 @@ abstract class AbstractChronicleMap<K, V> extends AbstractMap<K, V>
 
     @Override
     public final V putIfAbsent(K key, V value) {
+        checkValue(value);
         try (MapKeyContext<V> c = context(key)) {
             // putIfAbsent() shouldn't actually put most of the time,
             // so check if the key is present under read lock first:
@@ -87,6 +89,8 @@ abstract class AbstractChronicleMap<K, V> extends AbstractMap<K, V>
         }
     }
 
+    abstract void checkValue(V value);
+
     @Override
     @SuppressWarnings("unchecked")
     public final V get(Object key) {
@@ -137,6 +141,7 @@ abstract class AbstractChronicleMap<K, V> extends AbstractMap<K, V>
 
     @Override
     public <R> R getMapped(K key, @NotNull Function<? super V, R> function) {
+        requireNonNull(function);
         try (MapKeyContext<V> c = context(key)) {
             return c.containsKey() ? function.apply(c.get()) : null;
         }
@@ -144,6 +149,7 @@ abstract class AbstractChronicleMap<K, V> extends AbstractMap<K, V>
 
     @Override
     public V putMapped(K key, @NotNull UnaryOperator<V> unaryOperator) {
+        requireNonNull(unaryOperator);
         try (MapKeyContext<V> c = context(key)) {
             // putMapped() should find a value, update & put most of the time,
             // so don't try to check key presence under read lock first,
@@ -193,6 +199,7 @@ abstract class AbstractChronicleMap<K, V> extends AbstractMap<K, V>
     public final boolean remove(Object key, Object value) {
         if (value == null)
             return false; // CHM compatibility; General ChronicleMap policy is to throw NPE
+        checkValue((V) value);
         try (MapKeyContext<V> c = context((K) key)) {
             // remove(key, value) should find the entry & remove most of the time,
             // so don't try to check key presence and value equivalence under read lock first,
@@ -204,6 +211,7 @@ abstract class AbstractChronicleMap<K, V> extends AbstractMap<K, V>
 
     @Override
     public final V replace(K key, V value) {
+        checkValue(value);
         try (MapKeyContext<V> c = context(key)) {
             // replace(key, value) should find the key & put the value most of the time,
             // so don't try to check key presence under read lock first,
@@ -223,6 +231,8 @@ abstract class AbstractChronicleMap<K, V> extends AbstractMap<K, V>
 
     @Override
     public final boolean replace(K key, V oldValue, V newValue) {
+        checkValue(oldValue);
+        checkValue(newValue);
         try (MapKeyContext<V> c = context(key)) {
             // replace(key, old, new) should find the entry & put new value most of the time,
             // so don't try to check key presence and value equivalence under read lock first,

src/main/java/net/openhft/chronicle/map/BytesChronicleMap.java

@@ -70,6 +70,11 @@ public class BytesChronicleMap extends AbstractChronicleMap<Bytes, Bytes> {
         return context;
     }
 
+    @Override
+    void checkValue(Bytes value) {
+        Objects.requireNonNull(value);
+    }
+
     @Override
     public Class<Bytes> keyClass() {
         return Bytes.class;

src/main/java/net/openhft/chronicle/map/Objects.java

@@ -40,4 +40,9 @@ final class Objects {
                 o != null && builder.getClass() == o.getClass() &&
                         builder.toString().equals(o.toString());
     }
+
+    static void requireNonNull(Object obj) {
+        if (obj == null)
+            throw new NullPointerException();
+    }
 }

src/main/java/net/openhft/chronicle/map/VanillaChronicleMap.java

@@ -370,6 +370,7 @@ class VanillaChronicleMap<K, KI, MKI extends MetaBytesInterop<K, ? super KI>,
         }
     }
 
+    @Override
     final void checkValue(Object value) {
         if (vClass != Void.class && !vClass.isInstance(value)) {
             throw new ClassCastException("Value must be a " + vClass.getName() +