Java--集合

import java.util.*;
class TestSet
{
public static void main( String[] args){
Set<String> set = new HashSet<String>();
//Set<String> set = new TreeSet<String>();
set.add("Brazil");
set.add("Russia");
set.add("India");
set.add("China");
set.add("South Africa");

System.out.println( set.contains("China") );

for( String obj : set )
System.out.println( obj );

}
}