java - get wrong output of a recursive method -

    public static int getindexof(char ch, string str) {     if (str == null || str.equals("")) {         return 0;      //base case     }else{         char first = str.charat(0);         if (ch != first) {             return -1;      //returns -1 when character cannot found within string         }else{             int rest = str.length() - 1;             if (str.charat(rest) == ch) {                 return rest;              }             return lastindexof(ch, str.substring(0, rest));             //recursive case         }     } } 

this method returns index of input character of input string. however, when run in interaction plane, returns wrong number. example, when enter 'a' , "peach", supposed return 2, returns -1. method should return -1 when character cannot found in string. can tell me how deal it? thank you!

well why don't step through logic , see happens.

getindexof('a', "peach") 

method goes in, string isn't null or empty falls through next line of code.

char first = str.charat(0); // 'p'  if (ch != first) {  // 'p' equal 'a'? no. return -1         return -1; 

and rest of logic never execute. can see how fix problem?