Question

 String text = "select ename from emp";

I want to know the space index after the word from. How to do it?

Answer 1

If you’re specifically looking for the index of the first space after the word “from”, you can use:

text.substring(text.indexOf("from")).indexOf(' ');

If you’re trying to do something more general, than you’ll need to give a bit more information. But the indexOf() method will probably be very useful to you.

Edit: This should actually be

text.indexOf(' ', text.indexOf("from"));

The first version returns the index relative to “from”, whereas the second returns the index relative to the original string. (thanks @jpm)

This loop will find all space characters in the given string:

int index = text.indexOf(' ');
while (index >= 0) {
    System.out.println(index);
    index = text.indexOf(' ', index + 1);
}