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Java String indexOf() Method

Java String indexOf() Method

The indexOf() method in Java String is used to returns the position of the first occurrence of specified character in a string.

Syntax

There are four types of indexOf() methods:

public int indexOf(String str)
public int indexOf(String str, int fromIndex)
public int indexOf(int char)
public int indexOf(int char, int fromIndex)

Parameter

str - This parameter is used to represents A String value, to search for

fromIndex - This parameter is used to represents An int value of the index position to start the search from

Char - This parameter is used to represents An int value of a single character, e.g 'A', or a Unicode value

Technical Details

Returns - It is used to return An int value which represents the index of the first occurrence of the character in the string, or -1 if it never occurs

Java String indexOf() Method Example 1


public class MyClass 
{
  public static void main(String[] args) 
  {
    String myStrln1 = "Education breeds confidence, Confidence breeds Hope, Hope breeds peace.";
    System.out.println(myStrln1.indexOf("breeds"));
  }
}

Output: 10

Java String indexOf() Method Example 2


public class MyClass
{  
    public static void main(String[] args) 
	{      
        String n1 = "This is the best learning platform";         
        int index = n1.indexOf("learning", 10);  
        System.out.println("index of substring "+index);  
        index = n1.indexOf("learning", 20); 
        System.out.println("index of substring "+index);          
    }  
}  

Output: index of substring 17
index of substring -1