Question

Possible Duplicate:
java String concatenation

How to Improve performance of this chunk of code :

public static String concatStrings(Vector strings) {
    String returnValue = "";

    Iterator iter = strings.iterator();
    while( iter.hasNext() ) {
        returnValue += (String)iter.next();
    }

    return returnValue;
}

Answer 1

You might look at using StringBuilder, rather than doing += with the individual strings. Strings are immutable in Java, which means that once you create a String object, you cannot modify it. Using += on strings in a loop will result in the creation of many separate String instances, which may create performance problems. StringBuilder can concatenate Strings without having to create new instances, which may save some time, depending on the exact scenario.