How to upper case every first letter of word in a string?

Here is the code

    String source = "hello good old world";
    StringBuffer res = new StringBuffer();

    String[] strArr = source.split(" ");
    for (String str : strArr) {
        char[] stringArray = str.trim().toCharArray();
        stringArray[0] = Character.toUpperCase(stringArray[0]);
        str = new String(stringArray);

        res.append(str).append(" ");
    }

    System.out.print("Result: " + res.toString().trim());

Have a look at ACL WordUtils.

WordUtils.capitalize("your string") == "Your String"