How To Compile And Run A Java Program Locally

Introduction

Java is a widely used programming language known for its versatility and portability. To bring a Java program to life, you need to compile it into bytecode and then run it using the Java Virtual Machine (JVM). In this article, we will walk you through the process of compiling and running a Java program, providing a step-by-step guide to help you get started.

Step 1: Install Java Development Kit (JDK)

Before you begin, ensure that you have the Java Development Kit (JDK) installed on your system. The JDK includes the Java compiler (javac) and other tools necessary for compiling and running Java programs. You can download the JDK from the official Oracle website

 ( https://www.oracle.com/java/technologies/javase-jdk11-downloads.html) and follow the installation instructions for your operating system.

Step 2: Write Your Java Program

Using a text editor or an integrated development environment (IDE) like IntelliJ IDEA or Eclipse, write your Java program. Begin by creating a new Java source file with a .java extension. Make sure to define a class with a main() method, as it serves as the entry point for program execution. Add your desired code within the main() method to implement the functionality of your program.

Step 3: Save Your Java Program

Save your Java program with a .java file extension. It is good practice to use a meaningful and descriptive filename that reflects the purpose of your program. For example, if you are creating a program to calculate the area of a circle, you could name your file CircleArea.java.

Step 4: Open a Terminal or Command Prompt

To compile and run your Java program, you will need to use a terminal or command prompt. Open a terminal window on macOS or Linux, or a command prompt on Windows.

Step 5: Navigate to the Program Directory

Using the terminal or command prompt, navigate to the directory where your Java program is saved. You can use the 'cd' command to change directories. For example, if your program is saved on the desktop, you can navigate to it by running:

Step 6: Compile Your Java Program

To compile your Java program, use the javac command followed by the name of your Java source file. For example, if your program is named CircleArea.java, run the following command:

If there are no syntax errors in your program, the Java compiler will generate a bytecode file named CircleArea.class.

Step 7: Run Your Java Program

Once your Java program has been successfully compiled, you can run it using the java command followed by the name of the class containing the main() method. For example, if your main class is CircleArea, run the following command:

The JVM will execute your Java program, and if all goes well, you will see the output in the terminal or command prompt.


Conclusion

Compiling and running a Java program involves a few simple steps: installing the JDK, writing your program, saving it with a .java extension, navigating to the program directory in a terminal or command prompt, compiling the program using javac, and running it using java. By following this step-by-step guide, you can successfully compile and run your Java programs. With Java's portability and broad support, you can create applications that run on various platforms.