Clean serializers and ThreadLocal fields of VanillaChronicleMap on close()

src/main/java/net/openhft/chronicle/hash/impl/VanillaChronicleHash.java

@@ -657,15 +657,20 @@ public abstract class VanillaChronicleHash<K,
     @Override
     public final void close() {
         if (resources.releaseManually()) {
-            // Don't try to execute cleaner.clean() and ChronicleHashCloseOnExitHook.remove() from
-            // finally section of try block wrapping resources.releaseManually(), because
-            // Releases nothing after resources.releaseManually(), only removes the cleaner
-            // from the internal linked list of all cleaners.
-            cleaner.clean();
-            ChronicleHashCloseOnExitHook.remove(this);
+            cleanupOnClose();
         }
     }
 
+    protected void cleanupOnClose() {
+        // Releases nothing after resources.releaseManually(), only removes the cleaner
+        // from the internal linked list of all cleaners.
+        cleaner.clean();
+        ChronicleHashCloseOnExitHook.remove(this);
+        // Make GC life easier
+        keyReader = null;
+        keyDataAccess = null;
+    }
+
     @Override
     public boolean isOpen() {
         return !resources.closed();

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

@@ -174,6 +174,15 @@ public class VanillaChronicleMap<K, V, R>
         cxt = new ThreadLocal<>();
     }
 
+    @Override
+    protected void cleanupOnClose() {
+        super.cleanupOnClose();
+        // Make GC life easier
+        valueReader = null;
+        valueDataAccess = null;
+        cxt = null;
+    }
+
     public final V checkValue(Object value) {
         if (!valueClass.isInstance(value)) {
             throw new ClassCastException(toIdentityString() + ": Value must be a " +
@@ -297,6 +306,9 @@ public class VanillaChronicleMap<K, V, R>
     }
 
     final ChainingInterface q() {
+        ThreadLocal<ContextHolder> cxt = this.cxt;
+        if (cxt == null)
+            throw new ChronicleHashClosedException(this);
         ContextHolder contextHolder = cxt.get();
         if (contextHolder == null) {
             ChainingInterface queryContext = newQueryContext();
@@ -327,6 +339,9 @@ public class VanillaChronicleMap<K, V, R>
     }
 
     final ChainingInterface i() {
+        ThreadLocal<ContextHolder> cxt = this.cxt;
+        if (cxt == null)
+            throw new ChronicleHashClosedException(this);
         ContextHolder contextHolder = cxt.get();
         if (contextHolder == null) {
             ChainingInterface iterationContext = newIterationContext();