Finding second occurrence of a substring in a string in Java

We are given a string, say, "itiswhatitis" and a substring, say, "is". I need to find the index of 'i' when the string "is" occurs a second time in the original string.

String.indexOf("is") will return 2 in this case. I want the output to be 10 in this case.

Use overloaded version of indexOf(), which takes the starting index (fromIndex) as 2nd parameter:

str.indexOf("is", str.indexOf("is") + 1);

I am using: Apache Commons Lang: StringUtils.ordinalIndexOf()

StringUtils.ordinalIndexOf("Java Language", "a", 2)

int first = string.indexOf("is");
int second = string.indexOf("is", first + 1);

This overload starts looking for the substring from the given index.