转变为逆波兰表示式的代码报错：堆栈溢出，怎么解决？

Question

1. import java.util.Stack;  
2. import javax.swing.text.ChangedCharSetException;  
3. publicclass T {  
4.     publicstaticvoid main(String[] args){  
5.          System.out.print("请输入算式(测试)：");  
6.          Scanner sc=new Scanner(System.in);  
7.             String formula=sc.nextLine();  
8.             System.out.print(change(formula));  
9.     }  
10. publicstatic Stack<String> change(String expression) {  
11.                 Stack<Character> s1=new Stack<>();s1.push('#');  
12.                 Stack<String> s2=new Stack<>();  
13.                 char[] chars=expression.toCharArray();  
14.                 StringBuffer s=new StringBuffer();  
15.                 for(int i=0;i<chars.length;i++) {  
16.                     if(Character.isDigit(chars[i])) {  
17.                         while(Character.isDigit(chars[i])||chars[i]=='.') {  
18.                             s.append(chars[i]);  
19.                             }s2.push(s.toString());  
20.                     }  
21.                     else {  
22.                         switch(chars[i]){  
23.                             case'(':s1.push(chars[i]);break;  
24.                             case')':while(!s1.peek().equals('(')){  
25.                                     s2.push(s1.pop().toString());  
26.                                     }  
27.                                 s1.pop();break;  
28.                             case'+':  
29.                             case'-':  
30.                             case'/':  
31.                             case'*':;  
32.                                     s1.push(chars[i]);  
33.                                     if(get(chars[i+1])>get(chars[i])) {  
34.                                         s1.push(chars[i+1]);  
35.                                     }else {  
36.                                         s2.push(s1.peek().toString());  
37.                                     }  
38.                                         }  
39.                         }  
40.                 }return s2;  
41.             }  
42.             publicstaticint get(char c)  
43.                     {    int m=0;  
44.                             switch(c) {  
45.                             case'+':  
46.                             case'-':m=1;break;  
47.                             case'/':  
48.                             case'*':m=2;break;  
49.                             case'(':  
50.                             case')':m=0;break;  
51.                             case'#':m=-1;break;}  
52.                             return m;  
53.                         }     
54. }