Question

Here’s where I wish Java’s String class had a replaceLast method, bu it doesn’t and I’m getting the wrong results with my code.

I’m writing a program that searches a data structure for any items that match a string prefix. However, since I’m using an Iterator, the last item returned by the iter.next() call doesn’t match the pattern, so I want to change the search string so that the last character of the query is increased by one letter. My testing code is returning [C@b82368 with this code and An as titleSearch:

public String changeLastCharacter(String titleSearch) {
    char[] temp= titleSearch.toCharArray();

    char lastLetter= temp[temp.length-1];
    lastLetter++;
    temp[temp.length-1]= lastLetter;

    String newTitleSearch= temp.toString();
    return newTitleSearch;
}

First, what is the cause of the output from this code?
Second, is there a better way to execute my solution?

Answer 1

You want:

newTitleSearch = new String(temp);

The toString method is not overridden for arrays; it’s the usual Object.toString, intended for debugging. The above actually creates a string of the characters. An alternative is:

int len = titleSearch.length();
String allButLast = titleSearch.substring(0, len - 1);
newTitleSearch = allButLast + new Character(titleSearch.charAt(len - 1) + 1);