Question

how to sort variables X and negated varibles X’ alphabetic which are saved as string in Java?

Example: String string = "B*A'*D*H'"; result must
         String sortedString="A'*B*D*H'";

Answer 1

are the variables always separated with * ?
In that case it’d be very simple:

    String in = "B*A'*D*H'";
    String[] vars = in.split("\\*");

    Arrays.sort(vars);

    // Java is missing a simple php-like join function ;-(
    StringBuilder sorted = new StringBuilder();
    for(String s: vars){
        sorted.append(s);
        sorted.append("*");
    }
    sorted.deleteCharAt(sorted.length()-1);

and you’re done 😉