Java String Equality: `==` vs `equals()`

Unraveling the Mystery of String Equality in Java

When working with strings in Java, it’s essential to understand the difference between the == operator and the equals() method. These two concepts are often confused, but they serve distinct purposes in determining string equality.

The == Operator: A Reference Check

The == operator checks if two string objects are referencing the same memory location. In other words, it verifies if both variables point to the same object. This means that even if the strings have the same content, if they are stored in different memory locations, the == operator will return false.

The equals() Method: A Content Check

On the other hand, the equals() method checks if the content of two string objects is identical. It compares the actual characters within the strings, regardless of their memory locations. This means that even if the strings are stored in different memory locations, if their content is the same, the equals() method will return true.

Example 1: Differentiating == and equals()

Let’s consider an example to illustrate this concept:
“`java
String name1 = new String(“Programiz”);
String name2 = new String(“Programiz”);

System.out.println(name1 == name2); // returns false
System.out.println(name1.equals(name2)); // returns true
“
In this example,name1andname2are two separate string objects with the same content. The==operator returnsfalsebecause they are referencing different memory locations. However, theequals()method returnstrue` because their content is identical.

Example 2: The Same Object, Different Variables

Now, let’s consider another example:
“`java
String name1 = new String(“Programiz”);
String name2 = name1;

System.out.println(name1 == name2); // returns true
System.out.println(name1.equals(name2)); // returns true
“
In this case,name1andname2are referencing the same string object. Therefore, both the==operator and theequals()method returntrue`.

By understanding the difference between the == operator and the equals() method, you can write more accurate and efficient Java code when working with strings.