Java String equals() Method

The String.equals() method in Java is used to compare two strings for content equality. This guide will cover the method's usage, explain how it works, and provide examples to demonstrate its functionality.

Table of Contents

1. Introduction
2. equals Method Syntax
3. Examples
   • Comparing Equal Strings
   • Comparing Different Strings
   • Case Sensitivity
   • Handling Null Values
4. Conclusion

Introduction

The String.equals() method is a member of the String class in Java. It allows you to compare two strings to determine if they are exactly the same in terms of content. This method is essential for validating string inputs, ensuring data consistency, and performing equality checks.

equals Method Syntax

The syntax for the equals method is as follows:

public boolean equals(Object anObject)

• anObject: The object to be compared with the string. It is typically another string.

Examples

Comparing Equal Strings

The equals method can be used to compare two strings that are exactly the same.

Example

public class EqualsExample {
    public static void main(String[] args) {
        String str1 = "Hello, World!";
        String str2 = "Hello, World!";

        boolean areEqual = str1.equals(str2);

        System.out.println("Strings are equal: " + areEqual);
    }
}

Output:

Strings are equal: true

Comparing Different Strings

The equals method will return false if the strings being compared are not exactly the same.

Example

public class EqualsExample {
    public static void main(String[] args) {
        String str1 = "Hello, World!";
        String str2 = "Hello, Java!";

        boolean areEqual = str1.equals(str2);

        System.out.println("Strings are equal: " + areEqual);
    }
}

Output:

Strings are equal: false

Case Sensitivity

The equals method is case-sensitive, meaning it will distinguish between uppercase and lowercase characters.

Example

public class EqualsExample {
    public static void main(String[] args) {
        String str1 = "hello, world!";
        String str2 = "Hello, World!";

        boolean areEqual = str1.equals(str2);

        System.out.println("Strings are equal: " + areEqual);
    }
}

Output:

Strings are equal: false

Handling Null Values

The equals method can handle comparisons with null values safely. If the string being compared to is null, the method will return false.

Example

public class EqualsExample {
    public static void main(String[] args) {
        String str1 = "Hello, World!";
        String str2 = null;

        boolean areEqual = str1.equals(str2);

        System.out.println("Strings are equal: " + areEqual);
    }
}

Output:

Strings are equal: false

Conclusion

The String.equals() method in Java is a fundamental tool for comparing strings for content equality. By understanding how to use this method, you can accurately check if two strings are the same, considering case sensitivity and handling potential null values. Whether you are validating user input, ensuring data consistency, or performing equality checks, the equals method provides a reliable solution for these tasks.