多选题 Given:
1. public class Twine {
2. public static void main (String[] args) {
3. String s="";
4. StringBuffer sb1=new StringBuffer("hi");
5. StringBuffer sb2=new StringBuffer("hi");
6. StringBuffer sb3=new StringBuffer(sb2);
7. StringBuffer sb4=sb3;
8. if(sb1.equals(sb2)) s += "1 ";
9. if(sb2.equals(sb3)) s += "2 ";
10. if(sb3.equals(sb4)) s += "3 ";
11. String s2="hi";
12. String s3="hi";
13. String s4=s3;
14. if(s2.equals(s3)) s += "4 ";
15. if(s3.equals(s4)) s += "5 ";
16. System.out.println(s);
17. }
18. }
What is the result?