diff --git a/src/main/java/com/moilioncircle/redis/replicator/util/ByteArrayMap.java b/src/main/java/com/moilioncircle/redis/replicator/util/ByteArrayMap.java
index 64f10581c1b4a20a0301b68fd7fe563e633c7ba6..3608eed04371e2234b1f247adf5756edeee47f13 100644
--- a/src/main/java/com/moilioncircle/redis/replicator/util/ByteArrayMap.java
+++ b/src/main/java/com/moilioncircle/redis/replicator/util/ByteArrayMap.java
@@ -34,69 +34,70 @@ import java.util.Set;
 //@NonThreadSafe
 public class ByteArrayMap implements Map<byte[], byte[]>, Serializable {
     private static final long serialVersionUID = 1L;
-    
+
     protected final Map<Element, Element> map;
-    
+
     public ByteArrayMap(Map<? extends byte[], ? extends byte[]> m) {
         this(true, m);
     }
-    
+
     public ByteArrayMap(boolean ordered, Map<? extends byte[], ? extends byte[]> m) {
         this(ordered, m == null ? 0 : m.size(), 0.75f);
         putAll(m);
     }
-    
+
     public ByteArrayMap() {
         this(true);
     }
-    
+
     public ByteArrayMap(boolean ordered) {
         this(ordered, 16);
     }
-    
+
     public ByteArrayMap(boolean ordered, int initialCapacity) {
         this(ordered, initialCapacity, 0.75f);
     }
-    
+
     public ByteArrayMap(boolean ordered, int initialCapacity, float loadFactor) {
         if (ordered) map = new LinkedHashMap<>(initialCapacity, loadFactor);
         else map = new HashMap<>(initialCapacity, loadFactor);
     }
-    
+
     @Override
     public int size() {
         return map.size();
     }
-    
+
     @Override
     public boolean isEmpty() {
         return map.isEmpty();
     }
-    
+
     @Override
     public boolean containsKey(Object key) {
         if (key != null && !(key instanceof byte[])) return false;
         return map.containsKey(new Element((byte[]) key));
     }
-    
+
     @Override
     public boolean containsValue(Object value) {
         if (value != null && !(value instanceof byte[])) return false;
         return map.containsValue(new Element((byte[]) value));
     }
-    
+
     @Override
     public byte[] get(Object key) {
         if (key != null && !(key instanceof byte[])) return null;
-        return map.get(new Element((byte[]) key)).bytes;
+        Element element = map.get(new Element((byte[]) key));
+        return element != null ? element.bytes : null;
     }
-    
+
     @Override
     public byte[] put(byte[] key, byte[] value) {
         Element element = map.put(new Element(key), new Element(value));
         return element != null ? element.bytes : null;
     }
-    
+
     @Override
     public void putAll(Map<? extends byte[], ? extends byte[]> m) {
         if (m == null) return;
@@ -104,42 +105,42 @@ public class ByteArrayMap implements Map<byte[], byte[]>, Serializable {
             put(entry.getKey(), entry.getValue());
         }
     }
-    
+
     @Override
     public byte[] remove(Object key) {
         if (key != null && !(key instanceof byte[])) return null;
         return map.remove(new Element((byte[]) key)).bytes;
     }
-    
+
     @Override
     public void clear() {
         map.clear();
     }
-    
+
     @Override
     public Set<byte[]> keySet() {
         return new KeySet();
     }
-    
+
     @Override
     public Collection<byte[]> values() {
         return new Values();
     }
-    
+
     @Override
     public Set<Entry<byte[], byte[]>> entrySet() {
         return new EntrySet();
     }
-    
+
     public static final class Element implements Serializable {
         private static final long serialVersionUID = 1L;
-    
+
         final byte[] bytes;
-    
+
         Element(byte[] bytes) {
             this.bytes = bytes;
         }
-        
+
         @Override
         public boolean equals(Object o) {
             if (this == o) return true;
@@ -147,30 +148,30 @@ public class ByteArrayMap implements Map<byte[], byte[]>, Serializable {
             Element key = (Element) o;
             return Arrays.equals(bytes, key.bytes);
         }
-        
+
         @Override
         public int hashCode() {
             return Arrays.hashCode(bytes);
         }
     }
-    
+
     private final class EntrySet extends AbstractSet<Entry<byte[], byte[]>> {
-        
+
         @Override
         public final int size() {
             return ByteArrayMap.this.size();
         }
-        
+
         @Override
         public final void clear() {
             ByteArrayMap.this.clear();
         }
-        
+
         @Override
         public final Iterator<Entry<byte[], byte[]>> iterator() {
             return new EntryIterator();
         }
-        
+
         @Override
         public final boolean contains(Object o) {
             if (!(o instanceof Map.Entry)) return false;
@@ -185,7 +186,7 @@ public class ByteArrayMap implements Map<byte[], byte[]>, Serializable {
             byte[] val = ByteArrayMap.this.get(key);
             return Arrays.equals(val, value);
         }
-        
+
         @Override
         public final boolean remove(Object o) {
             if (!(o instanceof Map.Entry)) return false;
@@ -203,148 +204,148 @@ public class ByteArrayMap implements Map<byte[], byte[]>, Serializable {
             return false;
         }
     }
-    
+
     private final class KeySet extends AbstractSet<byte[]> {
-        
+
         @Override
         public final int size() {
             return ByteArrayMap.this.size();
         }
-        
+
         @Override
         public final void clear() {
             ByteArrayMap.this.clear();
         }
-        
+
         @Override
         public final Iterator<byte[]> iterator() {
             return new KeyIterator();
         }
-        
+
         @Override
         public final boolean contains(Object o) {
             return ByteArrayMap.this.containsKey(o);
         }
-        
+
         @Override
         public final boolean remove(Object key) {
             return ByteArrayMap.this.remove(key) != null;
         }
     }
-    
+
     private final class Values extends AbstractCollection<byte[]> {
-        
+
         @Override
         public final int size() {
             return ByteArrayMap.this.size();
         }
-        
+
         @Override
         public final void clear() {
             ByteArrayMap.this.clear();
         }
-        
+
         @Override
         public final Iterator<byte[]> iterator() {
             return new ValueIterator();
         }
-        
+
         @Override
         public final boolean contains(Object o) {
             return containsValue(o);
         }
-        
+
     }
-    
+
     private final class KeyIterator implements Iterator<byte[]> {
-    
+
         private final Iterator<Element> iterator = map.keySet().iterator();
-        
+
         @Override
         public boolean hasNext() {
             return iterator.hasNext();
         }
-    
+
         @Override
         public byte[] next() {
             return iterator.next().bytes;
         }
-    
+
         @Override
         public void remove() {
             iterator.remove();
         }
     }
-    
+
     private final class ValueIterator implements Iterator<byte[]> {
-        
+
         private final Iterator<Element> iterator = map.values().iterator();
-        
+
         @Override
         public boolean hasNext() {
             return iterator.hasNext();
         }
-        
+
         @Override
         public byte[] next() {
             return iterator.next().bytes;
         }
-        
+
         @Override
         public void remove() {
             iterator.remove();
         }
     }
-    
+
     private final class EntryIterator implements Iterator<Map.Entry<byte[], byte[]>> {
-        
+
         private final Iterator<Map.Entry<Element, Element>> iterator = map.entrySet().iterator();
-        
+
         @Override
         public boolean hasNext() {
             return iterator.hasNext();
         }
-        
+
         @Override
         public Entry<byte[], byte[]> next() {
             Map.Entry<Element, Element> v = iterator.next();
             return new Node(v.getKey().bytes, v.getValue().bytes);
         }
-        
+
         @Override
         public void remove() {
             iterator.remove();
         }
     }
-    
+
     public static final class Node implements Map.Entry<byte[], byte[]>, Serializable {
         private static final long serialVersionUID = 1L;
-        
+
         private byte[] value;
         private final byte[] key;
-        
+
         private Node(byte[] key, byte[] value) {
             this.key = key;
             this.value = value;
         }
-        
+
         @Override
         public byte[] getKey() {
             return key;
         }
-        
+
         @Override
         public byte[] getValue() {
             return this.value;
         }
-        
+
         @Override
         public byte[] setValue(byte[] value) {
             byte[] oldValue = this.value;
             this.value = value;
             return oldValue;
         }
-        
+
         @Override
         public boolean equals(Object o) {
             if (this == o) return true;
@@ -353,7 +354,7 @@ public class ByteArrayMap implements Map<byte[], byte[]>, Serializable {
             return Arrays.equals(value, node.value) &&
                     Arrays.equals(key, node.key);
         }
-        
+
         @Override
         public int hashCode() {
             int result = Arrays.hashCode(value);