Java compilation and execution flow - Mini Project: Build & Apply

Java Compilation and Execution Flow

📖 Scenario: You are learning how Java programs are compiled and run. Understanding this flow helps you know what happens when you write and run Java code.

🎯 Goal: Build a simple Java program step-by-step to see how compilation and execution work together.

📋 What You'll Learn

Create a Java class with a main method

Declare a variable inside the main method

Print the variable value to the console

Understand the order of compilation and execution

💡 Why This Matters

🌍 Real World

Java programs are everywhere, from mobile apps to large servers. Knowing how to write and run Java code is the first step to building these applications.

💼 Career

Understanding Java compilation and execution is essential for software developers working with Java, enabling them to write, debug, and run programs effectively.

1

Create a Java class with a main method

Write a Java class named FlowDemo with a public static void main(String[] args) method. Leave the method body empty for now.

Java

public class FlowDemo {
    public static void main(String[] args) {
        // Your code here
    }
}

Need a hint?

The main method is the entry point for Java programs. It must be public static void main(String[] args).

2

Declare a variable inside the main method

Inside the main method, declare an integer variable named number and set it to 10.

Java

public class FlowDemo {
    public static void main(String[] args) {
        // Declare int number = 10 here
    }
}

Need a hint?

Use int number = 10; inside the main method to declare the variable.

3

Print the variable value to the console

Add a line inside the main method to print the value of number using System.out.println.

Java

public class FlowDemo {
    public static void main(String[] args) {
        int number = 10;
        // Print number here
    }
}

Need a hint?

Use System.out.println(number); to print the value to the console.

4

Run the program and see the output

Compile and run the FlowDemo class. The program should print 10 to the console.

Java

// Run the program to see the output

Need a hint?

Use javac FlowDemo.java to compile and java FlowDemo to run the program in your terminal or command prompt.