What are the 4 basic things in Java?

The four basic things in Java, which serve as the building blocks for learning the language, include:

1. Classes and Objects

• Class: A blueprint or template for creating objects. A class defines the properties and behaviors (methods) that the objects created from it will have.
• Object: An instance of a class that represents real-world entities with attributes (fields) and behaviors (methods).

Example:

class Car {
    String model;
    int year;
    
    void drive() {
        System.out.println("The car is driving.");
    }
}

public class Main {
    public static void main(String[] args) {
        Car myCar = new Car();  // Creating an object
        myCar.drive();  // Calling a method on the object
    }
}

2. Variables and Data Types

Variables in Java are containers for storing data, and each variable must be declared with a specific data type (e.g., int, String, boolean), which defines the kind of data the variable can hold.

Example:

int age = 25;
String name = "John";
boolean isStudent = true;

3. Control Flow Statements

Control flow statements manage the flow of execution in a Java program. Common control flow structures include:

• if-else statements for conditional logic.
• for, while loops for repeating tasks.

Example:

int num = 10;

if (num > 5) {
    System.out.println("Number is greater than 5");
} else {
    System.out.println("Number is 5 or less");
}

for (int i = 0; i < 5; i++) {
    System.out.println(i);
}

4. Methods (Functions)

Methods in Java define a block of code that performs a specific task. Methods allow for code reuse and modular programming.

Example:

public class Example {
    public static void main(String[] args) {
        greet();  // Calling the greet method
    }

    static void greet() {
        System.out.println("Hello, world!");
    }
}

Conclusion

In summary, the four basic things you should focus on when learning Java are classes and objects, variables and data types, control flow statements, and methods. Mastering these concepts will provide a solid foundation to tackle more complex Java programming topics.

For further learning, you can explore the official Oracle Java Documentation and tutorials from GeeksforGeeks.