<NME> Pair.java
<BEF> package edu.neu.ccs.pyramid.util;

/**
 * Created by chengli on 8/19/14.
 */
public class Pair<A,B> {
    private A first;
    private B second;

    public Pair(A first, B second) {
        this.first = first;
        this.second = second;
    }

    public Pair() {
    }

    public A getFirst() {
        return first;
    }

    public Pair<A, B> setFirst(A first) {
        this.first = first;
        return this;
    }

    public B getSecond() {
        return second;
    }

    public Pair<A, B> setSecond(B second) {
        this.second = second;
        return this;
    }

    @Override
    public String toString() {
        return "("+first+", "+second+")";
    }
}

<MSG> make class Pair Serializable

<DFF> @@ -1,9 +1,12 @@
 package edu.neu.ccs.pyramid.util;
 
+import java.io.Serializable;
+
 /**
  * Created by chengli on 8/19/14.
  */
-public class Pair<A,B> {
+public class Pair<A,B> implements Serializable{
+    private static final long serialVersionUID = 1L;
     private A first;
     private B second;
 

make class Pair Serializable