Java Concepts That Look Similar but Work Differently

Java has many features that look similar but behave differently. Understanding these differences is essential for writing efficient and error-free code. This blog will clarify some commonly confused Java concepts.

1. == vs .equals()

• == compares memory references (whether two objects are stored in the same memory location).
• .equals() compares values (whether two objects contain the same data).

Example:

public class EqualityTest {
    public static void main(String[] args) {
        String a = new String("hello");
        String b = new String("hello");
        
        System.out.println(a == b);      // false (different objects in memory)
        System.out.println(a.equals(b)); // true  (same content)
        
        String c = "hello";
        String d = "hello";
        System.out.println(c == d);      // true (same string pool reference)
    }
}

2. final vs finally vs finalize

• final → Used to define constants, prevent method overriding, and prevent inheritance.
• finally → A block that always executes after a try-catch block.
• finalize → A method in Object class, called by the Garbage Collector before reclaiming an object’s memory.

Example:

class FinalExample {
    final int x = 10;

void test() {
        // x = 20; //…