Added AsmFieldSerializer.

Minor updates.

.classpath

@@ -4,6 +4,6 @@
 	<classpathentry excluding="**/.svn/*" kind="src" path="test"/>
 	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/>
 	<classpathentry kind="lib" path="build/junit-4.6.jar"/>
-	<classpathentry exported="true" kind="lib" path="lib/minlog-1.1.jar"/>
+	<classpathentry kind="lib" path="lib/asm-3.2.jar" sourcepath="C:/Dev/Java/Misc/asm-3.2-src/src"/>
 	<classpathentry kind="output" path="bin"/>
 </classpath>

src/com/esotericsoftware/kryo/Kryo.java

@@ -9,6 +9,7 @@
 import java.nio.ByteBuffer;
 import java.util.Collection;
 import java.util.HashMap;
+import java.util.IdentityHashMap;
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicInteger;
 
@@ -44,7 +45,7 @@ protected Context initialValue () {
 	};
 
 	private final IntHashMap<RegisteredClass> idToRegisteredClass = new IntHashMap(64);
-	private final HashMap<Class, RegisteredClass> classToRegisteredClass = new HashMap(64);
+	private final IdentityHashMap<Class, RegisteredClass> classToRegisteredClass = new IdentityHashMap(64);
 	private AtomicInteger nextClassID = new AtomicInteger(1);
 	private Object listenerLock = new Object();
 	private KryoListener[] listeners = {};
@@ -254,7 +255,7 @@ public Serializer getSerializer (Class type) {
 	 * Writes the ID of the specified class to the buffer. The ID will be an int for {@link #register(Class, Serializer) registered
 	 * classes}. If {@link #setAllowUnregisteredClasses(boolean) allowUnregisteredClasses} is true and the class was not explicitly
 	 * registered, the ID will be the class name String.
-	 * @param type Can be null (writes a special class ID for a null object).
+	 * @param type Can be null (writes a special ID for a null object).
 	 * @return The registered information for the class that was written, or null of the specified class was null.
 	 */
 	public RegisteredClass writeClass (ByteBuffer buffer, Class type) {
@@ -306,7 +307,7 @@ public RegisteredClass readClass (ByteBuffer buffer) {
 	/**
 	 * Writes the object's class ID to the buffer, then uses the serializer registered for that class to write the object to the
 	 * buffer.
-	 * @param object Can be null (writes a special class ID for a null object instead).
+	 * @param object Can be null (writes a special ID for a null object instead).
 	 */
 	public void writeClassAndObject (ByteBuffer buffer, Object object) {
 		if (object == null) {
@@ -324,7 +325,7 @@ public void writeClassAndObject (ByteBuffer buffer, Object object) {
 
 	/**
 	 * Uses the serializer registered for the object's class to write the object to the buffer.
-	 * @param object Can be null (writes a special class ID for a null object instead).
+	 * @param object Can be null (writes a special ID for a null object instead).
 	 */
 	public void writeObject (ByteBuffer buffer, Object object) {
 		if (object == null) {

src/com/esotericsoftware/kryo/Serializer.java

@@ -12,6 +12,9 @@
  * @author Nathan Sweet <[email protected]>
  */
 abstract public class Serializer {
+	static private final byte NULL_OBJECT = 0;
+	static private final byte NOT_NULL_OBJECT = 1;
+
 	private boolean canBeNull = true;
 
 	/**
@@ -30,10 +33,10 @@ public final void writeObject (ByteBuffer buffer, Object object) {
 		if (canBeNull) {
 			if (object == null) {
 				if (TRACE) trace("kryo", "Wrote object: null");
-				buffer.put((byte)0);
+				buffer.put(NULL_OBJECT);
 				return;
 			}
-			buffer.put((byte)1);
+			buffer.put(NOT_NULL_OBJECT);
 		}
 		writeObjectData(buffer, object);
 	}
@@ -49,7 +52,7 @@ public final void writeObject (ByteBuffer buffer, Object object) {
 	 * @return The deserialized object, or null if the object read from the buffer was a null.
 	 */
 	public final <T> T readObject (ByteBuffer buffer, Class<T> type) {
-		if (canBeNull && buffer.get() == 0) {
+		if (canBeNull && buffer.get() == NULL_OBJECT) {
 			if (TRACE) trace("kryo", "Read object: null");
 			return null;
 		}

src/com/esotericsoftware/kryo/serialize/ArraySerializer.java

@@ -81,10 +81,11 @@ public void writeObjectData (ByteBuffer buffer, Object array) {
 		// If element class is final (this includes primitives) then all elements are the same type.
 		Serializer elementSerializer = null;
 		Class elementClass = getElementClass(array.getClass());
+		boolean elementsCanBeNull = this.elementsCanBeNull && !elementClass.isPrimitive();
 		if (elementsAreSameType || Modifier.isFinal(elementClass.getModifiers()))
 			elementSerializer = kryo.getRegisteredClass(elementClass).serializer;
 		// Write array data.
-		writeArray(buffer, array, elementSerializer, 0, dimensions.length);
+		writeArray(buffer, array, elementSerializer, 0, dimensions.length, elementsCanBeNull);
 		if (TRACE) {
 			StringBuilder stringBuffer = new StringBuilder(16);
 			for (int i = 0, n = dimensions.length; i < n; i++) {
@@ -96,7 +97,8 @@ public void writeObjectData (ByteBuffer buffer, Object array) {
 		}
 	}
 
-	private void writeArray (ByteBuffer buffer, Object array, Serializer elementSerializer, int dimension, int dimensionCount) {
+	private void writeArray (ByteBuffer buffer, Object array, Serializer elementSerializer, int dimension, int dimensionCount,
+		boolean elementsCanBeNull) {
 		int length = Array.getLength(array);
 		if (dimension > 0) {
 			// Write array length. With Java's "jagged arrays" this could be less than the dimension size.
@@ -108,7 +110,8 @@ private void writeArray (ByteBuffer buffer, Object array, Serializer elementSeri
 			Object element = Array.get(array, i);
 			if (elementsAreArrays) {
 				// Nested array.
-				if (element != null) writeArray(buffer, element, elementSerializer, dimension + 1, dimensionCount);
+				if (element != null)
+					writeArray(buffer, element, elementSerializer, dimension + 1, dimensionCount, elementsCanBeNull);
 			} else if (elementSerializer != null) {
 				// Use same serializer for all elements.
 				if (elementsCanBeNull)
@@ -136,11 +139,12 @@ public <T> T readObjectData (ByteBuffer buffer, Class<T> type) {
 		// Get element serializer if all elements are the same type.
 		Serializer elementSerializer = null;
 		Class elementClass = getElementClass(type);
+		boolean elementsCanBeNull = this.elementsCanBeNull && !elementClass.isPrimitive();
 		if (elementsAreSameType || Modifier.isFinal(elementClass.getModifiers()))
 			elementSerializer = kryo.getRegisteredClass(elementClass).serializer;
 		// Create array and read in the data.
 		T array = (T)Array.newInstance(elementClass, dimensions);
-		readArray(buffer, array, elementSerializer, elementClass, 0, dimensions);
+		readArray(buffer, array, elementSerializer, elementClass, 0, dimensions, elementsCanBeNull);
 		if (TRACE) {
 			StringBuilder stringBuffer = new StringBuilder(16);
 			for (int i = 0; i < dimensionCount; i++) {
@@ -154,7 +158,7 @@ public <T> T readObjectData (ByteBuffer buffer, Class<T> type) {
 	}
 
 	private void readArray (ByteBuffer buffer, Object array, Serializer elementSerializer, Class elementClass, int dimension,
-		int[] dimensions) {
+		int[] dimensions, boolean elementsCanBeNull) {
 		boolean elementsAreArrays = dimension < dimensions.length - 1;
 		int length;
 		if (dimension == 0)
@@ -165,7 +169,8 @@ private void readArray (ByteBuffer buffer, Object array, Serializer elementSeria
 			if (elementsAreArrays) {
 				// Nested array.
 				Object element = Array.get(array, i);
-				if (element != null) readArray(buffer, element, elementSerializer, elementClass, dimension + 1, dimensions);
+				if (element != null)
+					readArray(buffer, element, elementSerializer, elementClass, dimension + 1, dimensions, elementsCanBeNull);
 			} else if (elementSerializer != null) {
 				// Use same serializer (and class) for all elements.
 				if (elementsCanBeNull)