String contains() Method in Java with Example

Syntax of String "Contain" method

public boolean String.contains(CharSequence s)

Parameters

s − This is the sequence to search

Return Value

This method returns true only if this string contains "s" else false.

Exception

NullPointerException − if the value of s is null.

Example 1:

public class Sample_String {
    public static void main(String[] args) {
        String str_Sample = "This is a String contains Example";
        //Check if String contains a sequence
        System.out.println("Contains sequence 'ing': " + str_Sample.contains("ing"));
        System.out.println("Contains sequence 'Example': " + str_Sample.contains("Example"));
        //String contains method is case sensitive  
        System.out.println("Contains sequence 'example': " + str_Sample.contains("example"));
        System.out.println("Contains sequence 'is String': " + str_Sample.contains("is String"));
    }
}

Output:

Contains sequence 'ing': true
Contains sequence 'Example': true
Contains sequence 'example': false
Contains sequence 'is String': false

When to use Contains() method?

It is a common case in programming when you want to check if specific String contains a particular substring. For example, If you want to test if the String "The big red fox" contains the substring "red." This method is useful in such situation.

Example 2: Java String contains() method in the if else Loop

public class IfExample {
    public static void main(String args[]) {
        String str1 = "Java string contains If else Example";
        // In If-else statements you can use the contains() method

        if (str1.contains("example")) {
            System.out.println("The Keyword :example: is found in given string");
        } else {
            System.out.println("The Keyword :example: is not found in the string");
        }
    }
}

Output:

The Keyword :example: is not found in the string