How to solve problem (testing with mutants in java)?

I have to implement algorithm for finding mutants in code. From input file, i have to reading some code for example;

public static void main(String[] args){
  int s = 0; 
  for (int i = 0; i < x.length; i++) { 
    s = s + x[i]; 
  } 
  System.out.println(s);
}

I have to create mutants using two rules: replacement of arithmetic operations and replacement of variables of the same type. For example: in the code above we have line with code s=s+x[i]; The + sign should be replaced by the - sign, so the first mutant would be;

public static void main(String[] args){
  int s = 0; 
  for (int i = 0; i < x.length; i++) { 
    s = s - x[i]; 
  } 
  System.out.println(s);
}

Second mutant would be;

public static void main(String[] args){
  int s = 0; 
  for (int i = 0; i < x.length; i++) { 
    s = s / x[i]; 
  } 
  System.out.println(s);
}

And so for each sign. Do the same with replacement of variables of the same type.

Mutants must be written to the output file.

I need a solution in Java. Please help?