How to change value of ArrayList element in java (when indexOf doesnt work)!

I've many question like this before, but every solution I've found involves the usage of indexOf. Just like here.

Well, I'm implementing a recursive descent parser, and after execution each production I've to print the production, something like "A = B 'token' (value of token) C". The problem arises when productions have many other productions and tokens, if I print it in the begining of the production I don't have the value of every token, if I print it in the end the final list of productions will be in an incorrect order.

So I'm doing something like this:

String s="";
productions.add(s);
A();
getToken();
B();
s=("A 'token' B");

You can see that in the method A() I might have something like that too, so I will be addind many s="" to the list, thus indexOf wont work. Currently I'm doing this:

String s="";
s+= productions.size();
productions.add(s);
A();
getToken();
B();
s=("A 'token' B");

But I don't find this solution anyhow elegant. There is a better way to do that?

Here is an example of what I'm trying to do, note that it won't work because you need a lexical analyser that implements the nextToken method

public class parser {
    ArrayList<String> productions = new ArrayList<>();
    void S(){
        //S = A '*' B
        String s="";
        productions.add(s);
        A();
        nextToken();
        B();
        s="S = A '*' B"
        printProductions();
    }

    void A(){
        //A = 'ctn' | B
        String s="";
        productions.add(s);
        if(!currentTk=ctn){
            s="A = B
            B();
        }else{
            s="A = 'ctn'
        }
    }

    void B(){
        //B = 'ctn' '+' 'ctn'
        String s="";
        productions.add(s);
        if(currentTk=ctn){
            nextToken();
            if(currentTk=ctn){
                if(currentTk=ctn){
                    nextToken();
                    s= "'ctn' '+' 'ctn'"
                }
            }
        }
    }
}