import java.util.*;
import com.bruceeckel.util.*;
class E_13_2 implements Comparator
{
  private String s1;
  private String s2;
  private E_13_2 e;
  E_13_2(String s1,String s2){
 this.s1=s1;
 this.s2=s2;
}
public boolean equals(Object o){
 return (o instanceof E_13_2)&&(s2==((E_13_2)o).s2);
}
public int compare(Object o1,Object o2){
 String s3=((E_13_2)o1).s2, s4=((E_13_2)o2).s2;
 return e.compare(s3,s4);
}
public String toString(){
 return "[s1:"+s1+"<>s2:"+s2+"]";
}
public static Arrays2.RandStringGenerator gen=
 new Arrays2.RandStringGenerator(8);
public static Generator generator(){
   return new Generator(){
 public Object next(){
  return new E_13_2((String)gen.next(),(String)gen.next());
  }
 };
}
}
public class E13Test
{
 public static void main(String args[]){
 E_13_2[] e13 = new E_13_2[10];
 Arrays2.fill(e13,E_13_2.generator());
 Arrays2.print("before sort() =>",e13);
 Arrays.sort(e13);
 Arrays2.print("after sort() =>",e13);
 }
}

before sort() => ([s1:dmOmrMCG<>s2:tuMsnVcf], [s1:CbWECTsI<>s2:AzTHfIcq], [s1:QASdXyRN<>s2:ydUhgXBj], [s1:jWLThZNP<>s2:pJnyGKiG], [s1:aqXwNAWq<>s2:dNmVZbuQ], [s1:KxKLcEQd<>s2:VIiAZiIt], [s1:ycDvsmYR<>s2:sBMFozNq], [s1:fbfcKGnd<>s2:tGEchRKv], [s1:wvQmPgJh<>s2:fJEDWkcG], [s1:FfaksBZv<>s2:lnhSLecY])
java.lang.ClassCastException
 at java.util.Arrays.mergeSort(Arrays.java:1152)
 at java.util.Arrays.mergeSort(Arrays.java:1163)
 at java.util.Arrays.sort(Arrays.java:1079)
 at E13Test.main(E13Test.java:38)
Exception in thread "main" 
输出完成 (耗时 0 秒) - 正常终止

public int compare(Object o1,Object o2);
  String s3=((E_13_2)o1).s2,s4=((E_13_2)o2).s2;
  return s3.compareTo(s4);
}