Please use java and implement your own stack implementation

Please use java and implement your own stack implementation

Implement a simple stack-based post-fix calculator. Your program should accept integer operands and the +, -, and * operators. Expressions should be entered one item per line with = on the final line to trigger the calculation and output of the result. Your program should detect invalid expressions (e.g., too few operands, too many operands).

Solution

                        String input = sb.toString();