Example strings
one thousand only
two hundred
twenty
seven
How do I change the first character of a string in capital letter and not change
If you only want to capitalize the first letter of a string named input and leave the rest alone:
String output = input.substring(0, 1).toUpperCase() + input.substring(1);
Now output will have what you want. Check that your input is at least one character long before using this, otherwise you'll get an exception.