Java String indexOf

The java string indexOf() method index of given character value or substring. If it is not found, it returns -1. The index counter starts from zero.

Signature

There are 4 types of indexOf method in java. The signature of indexOf methods are given below:

No.	Method	Description
1	int indexOf(int ch)	returns index position for the given char value
2	int indexOf(int ch, int fromIndex)	returns index position for the given char value and from index
3	int indexOf(String substring)	returns index position for the given substring
4	int indexOf(String substring, int fromIndex)	returns index position for the given substring and from index

Parameters

ch: char value i.e. a single character e.g. 'a'

fromIndex: index position from where index of the char value or substring is retured

substring: substring to be searched in this string

Returns

index of the string

Java String indexOf() method example

public class IndexOfExample{  

public static void main(String args[]){  

String s1="this is index of example";  

//passing substring  

int index1=s1.indexOf("is");//returns the index of is substring  

int index2=s1.indexOf("index");//returns the index of index substring  

System.out.println(index1+"  "+index2);//2 8  

  

//passing substring with from index  

int index3=s1.indexOf("is",4);//returns the index of is substring after 4th index  

System.out.println(index3);//5 i.e. the index of another is  

  

//passing char value  

int index4=s1.indexOf('s');//returns the index of s char value  

System.out.println(index4);//3  

}}  

Expected Output:

2  8
5

3