Java：在类的末尾“错过了返回语句”

Question

我正在编写用于汇编代码生成的java代码，但是我收到以下错误：

CodeGenerator.java:77：错误：缺少return语句     }     ^ 1错误

我检查了所有if-else语句，每个case返回一些值。问题是什么？

import java.util.*;

class CodeGenerator
{

    static String[] code = new String[100];
    static String[] reg = new String[100];
    public static void main(String[] args)
    {
        String[] arg1 = new String[] {"b","d","t","t","w"};
        String[] arg2 = new String[] {"c","c","v","u",""};
        String[] op = new String[] {"+","+","-","+",""};
        String[] result = new String[] {"t","v","u","w","a"};
        int temp1, temp2, tempReg, temp;
        int i=0;
        String opcode;

        for(i=0;i<=4;i++)
        {
            if(!(op[i].equals("=")))
            {
                temp1 = findReg(arg1[i]);
                temp2 = findReg(arg2[i]);
                if(temp1==-1 && temp2==-1)
                {
                    tempReg = genReg();
                    opcode = findInst(op[i]);
                    code[i] = "MOV "+arg1[i]+", R"+tempReg+"\n"+opcode+" "+arg2[i]+", R"+tempReg;
                    reg[tempReg]=result[i];
                }
                else if(temp1!=-1 && temp2!=-1)
                {
                    opcode = findInst(op[i]);
                    code[i]=opcode+" R"+temp1+", R"+temp2;
                    reg[temp2]=result[i];
                }
                else
                {
                    temp=findReg(arg1[i]);
                    if(temp!=-1)
                    code[i]="MOV R"+temp+", "+result[i];
                }
            }
        }
        for(i=0;i<=4;i++)
            System.out.println(code[i]);
    }

    static int genReg()
    {
        int i=0;
        while(reg[i]!=null)
            i++;
        return i;
    }

    static int findReg(String a)
    {
        int i=0;
        while(reg[i]!=null)
        {
            if(reg[i].equals(a))
                return i;
            else
                i++;
        }
        return -1;
    }

    static String findInst(String a)
    {
        if(a.equals("+"))
            return "ADD";
        else if(a.equals("-"))
            return "SUB";
    }
}