diff --git a/classpath/java/lang/Integer.java b/classpath/java/lang/Integer.java
index d30bb804b1..028d01e4e7 100644
--- a/classpath/java/lang/Integer.java
+++ b/classpath/java/lang/Integer.java
@@ -1,6 +1,6 @@
 package java.lang;
 
-public final class Integer extends Number {
+public final class Integer extends Number implements Comparable<Integer> {
   public static final Class TYPE = Class.forCanonicalName("I");
 
   public static final int MIN_VALUE = 0x80000000;
@@ -28,6 +28,10 @@ public final class Integer extends Number {
     return value;
   }
 
+  public int compareTo(Integer other) {
+    return value - other.value;
+  }
+
   public String toString() {
     return toString(value);
   }