Java is a versatile and widely-used programming language known for its portability and compatibility. Whether you’re a beginner taking your first steps in programming or an experienced developer working on complex applications, running a Java program is a fundamental skill to master. In this guide, I’ll walk you through the step-by-step process of running a Java program.
Before you can run Java programs, you need to ensure you have the Java Development Kit (JDK) installed on your computer. The JDK includes essential tools for Java development, including the Java Runtime Environment (JRE), which is necessary for running Java applications.
You can download the JDK from the official Oracle website(Oracle Java Download) or opt for alternative distributions like OpenJDK, which is open-source and widely used in the Java community. Follow the installation instructions for your specific operating system to set up the JDK.
With the JDK installed, you’re ready to write your Java code. You can use any text editor, such as Notepad (Windows), TextEdit (macOS), or a specialized Integrated Development Environment (IDE) like Eclipse, IntelliJ IDEA, or Visual Studio Code. Here’s a simple “Hello, World!” program to get started:
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello, World!");
}
}
In this example, we create a class named HelloWorld, which contains a main method—the entry point for your Java program. The System.out.println statement prints “Hello, World!” to the console.
Save this code in a file with a “.java” extension. For instance, you can name it “HelloWorld.java.“
Java is a compiled language, which means you must convert your human-readable code into bytecode that the Java Virtual Machine (JVM) can understand. To do this, open your command prompt (Windows) or terminal (macOS/Linux) and navigate to the directory where your Java file is located. Use the javac command followed by the name of your Java file to compile your code:
javac HelloWorld.java
If there are no syntax errors in your code, the compilation process will create a bytecode file with the same name as your class, but with a “.class” extension, such as “HelloWorld.class.“
Once your code is successfully compiled, you can run your Java program using the java command, followed by the name of the class containing the main method (in this case, “HelloWorld”):
java HelloWorld
If everything is set up correctly, you will see the following output displayed in the terminal: Hello, World!
Congratulations! You have successfully run your first Java program.
Running a Java program involves a few essential steps: installing the JDK, writing your code, compiling it, and finally, executing it. Java’s platform independence makes it an excellent choice for a wide range of applications, from desktop software to web applications and Android app development. As you continue your journey with Java, you’ll explore its rich ecosystem of libraries and tools, enabling you to build powerful and versatile applications.