equals() vs == in String

Overview

In Java, both == and equals() are used to compare objects, but they work differently when comparing Strings.

• == compares memory references (addresses)
• equals() compares actual string values (content)

Rule: Use equals() when comparing String values.

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Using == Operator

The == operator checks whether two references point to the same object in memory.

Example

String s1 = "Java";
String s2 = "Java";

System.out.println(s1 == s2); // true

Explanation

Both s1 and s2 refer to the same object in the String Constant Pool.

Memory representation

    String Pool

    +---------+
    | "Java"  |  ← s1, s2
    +---------+

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Using equals() Method

The equals() method compares the actual content of the strings.

Example

String s1 = new String("Java");
String s2 = new String("Java");

System.out.println(s1.equals(s2)); // true

Explanation

Even though s1 and s2 are different objects, their values are the same, so equals() returns true.

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Example Showing Difference

String s1 = new String("Java");
String s2 = new String("Java");

System.out.println(s1 == s2); // false
System.out.println(s1.equals(s2)); // true

Explanation

• == → compares memory addresses
• equals() → compares actual text

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Comparison Table

Feature	== Operator	equals() Method
Comparison type	Reference comparison	Value comparison
Checks	Memory address	String content
Works for objects	Yes	Yes
Recommended for strings	No	Yes

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When to Use

Use == when:

• You want to check if two references point to the same object.

Use equals() when:

• You want to compare actual string values.

Example

String s1 = "Java";
String s2 = "Java";

if(s1.equals(s2)){
    System.out.println("Strings are equal");
}

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Summary

• == compares memory references
• equals() compares string values
• Always use equals() for string content comparison
• == should only be used when checking object references