Why does java.lang.ArrayIndexOutOfBoundsException happen on this piece of code?

Question

public boolean felGissningar(char gi, int antalfel){
    if(antalfel>0){
    int test = 0;
    for (int i = 0; i<felGiss1.length; i++){
        if(gi == felGiss1[i]){
            test+=1;
        }
    }
    felGiss2 = new char[antalfel];
    for (int i = 0; i<felGiss1.length; i++){
        felGiss2[i]=felGiss1[i];
    }

    felGiss1 = new char[antalfel+1];
    for (int i =0;i<antalfel; i++){
        felGiss1[i]=felGiss2[i];
    }
    felGiss1[antalfel] = gi;
    System.out.println("1: "+String.valueOf(felGiss1));
    System.out.println("2: "+String.valueOf(felGiss2));
    if(test>0){
        return false;
    } else {
        return true;
    }
    }else {
        felGiss1 = new char[1];
        felGiss1[0]=gi;
        return true;
    }
}

antalfel means number of incorrect answers

After this boolean has returned false once it says java.lang.ArrayIndexOutOfBoundsException

what im trying to do is to not allow for the same wrong character twise.

Answer 1

Over here:

    felGiss2 = new char[antalfel];
    for (int i = 0; i<felGiss1.length; i++){
        felGiss2[i]=felGiss1[i];
    }

Since you didn't post where felGiss1 was created, if felGiss1.length is greater than felGiss2.length then it will produce an exception. Please change to:

    felGiss2 = new char[antalfel];
    for (int i = 0; i<felGiss1.length && i < fellGiss2.length; i++){
        felGiss2[i]=felGiss1[i];
    }