Top 5 Core Java Concepts Every Beginner Should Know

**Top 5 Core Java Concepts Every Beginner Should Know**

If you're starting your journey into Java programming, understanding these core concepts is essential. These principles form the foundation of Java and are frequently asked in interviews and real-world coding scenarios.

Core Java Concepts Cover Image

1. Classes and Objects

Java is an object-oriented language. Everything in Java revolves around **classes** (blueprints) and **objects** (real instances of classes).  

java

class Student {

  String name;

  void display() {

    System.out.println("Name: " + name);

  }

}

2. Inheritance

Inheritance allows one class to inherit the features (variables and methods) of another class using the extends keyword.
It promotes code reusability and hierarchical classification.

java
class Animal {
  void sound() { System.out.println("Animal sound"); }
}
class Dog extends Animal {
  void bark() { System.out.println("Dog barks"); }
}

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3. Encapsulation

Encapsulation is the process of wrapping data (variables) and code (methods) together as a single unit.
It’s done using private variables + public getters and setters.

java
class Account {
  private int balance = 1000;
  public int getBalance() { return balance; }
}

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4. Polymorphism

Polymorphism means "many forms". It allows the same method name to behave differently:

• Compile-time (Method Overloading)

• Run-time (Method Overriding)

java
class Calculator {
  int add(int a, int b) { return a + b; }
  double add(double a, double b) { return a + b; }
}

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5. Abstraction

Abstraction hides unnecessary details and shows only essential features using abstract classes or interfaces.

java
abstract class Vehicle {
  abstract void start();
}
class Car extends Vehicle {
  void start() { System.out.println("Car starts"); }
}