diff --git a/classpath/java/util/SortedMap.java b/classpath/java/util/SortedMap.java
new file mode 100644
index 0000000000..d7abb282ba
--- /dev/null
+++ b/classpath/java/util/SortedMap.java
@@ -0,0 +1,15 @@
+package java.util;
+
+public interface SortedMap<K, V> extends Map<K, V> {
+  public Comparator<? super K> comparator();
+  
+  public K firstKey();
+  
+  public K lastKey();
+  
+  public SortedMap<K, V> headMap(K toKey);
+  
+  public SortedMap<K, V> tailMap(K fromKey);
+  
+  public SortedMap<K, V> subMap(K fromKey, K toKey);
+}
diff --git a/classpath/java/util/TreeMap.java b/classpath/java/util/TreeMap.java
index e5be011a07..e7258255cd 100644
--- a/classpath/java/util/TreeMap.java
+++ b/classpath/java/util/TreeMap.java
@@ -14,7 +14,7 @@ import java.io.IOException;
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 
-public class TreeMap<K,V> implements Map<K,V> {
+public class TreeMap<K,V> implements SortedMap<K,V> {
   private final Comparator<K> comparator;
   private transient TreeSet<MyEntry<K,V>> set;
 
@@ -45,6 +45,39 @@ public class TreeMap<K,V> implements Map<K,V> {
     return avian.Data.toString(this);
   }
 
+  @Override
+  public Comparator<? super K> comparator() {
+    return comparator;
+  }
+
+  @Override
+  public K firstKey() {
+    return set.first().key;
+  }
+
+  @Override
+  public K lastKey() {
+    return set.last().key;
+  }
+
+  @Override
+  public SortedMap<K, V> headMap(K toKey) {
+    // TODO - this should be implemented, the trick is making the returned SortedMap backed by this TreeSet
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public SortedMap<K, V> tailMap(K fromKey) {
+    // TODO - this should be implemented, the trick is making the returned SortedMap backed by this TreeSet
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public SortedMap<K, V> subMap(K fromKey, K toKey) {
+    // TODO - this should be implemented, the trick is making the returned SortedMap backed by this TreeSet
+    throw new UnsupportedOperationException();
+  }
+
   public V get(Object key) {
     MyEntry<K,V> e = set.find(new MyEntry(key, null));
     return e == null ? null : e.value;