In this article, we will guide you through the process of compiling and running Java programs in Ubuntu. This tutorial is aimed at users who have basic knowledge of Ubuntu’s command-line interface and Java programming.
To compile and run Java programs in Ubuntu, you need to have Java Development Kit (JDK) installed on your system. Once JDK is installed, you can compile your Java program using the javac command followed by the name of your Java file. After successful compilation, you can run your Java program using the java command followed by the name of the class.
Prerequisites
Before we start, ensure that you have Java installed on your system. You can check this by using the java -version command in the terminal. If Java is not installed, you can follow this guide to install it.
Installing Java Development Kit (JDK)
Java Development Kit (JDK) is a software development environment used for developing Java applications. It includes the Java Runtime Environment (JRE), an interpreter/loader (java), a compiler (javac), an archiver (jar), a documentation generator (javadoc), and other tools needed in Java development.
To install JDK on your Ubuntu system, open the terminal and run the following command:
sudo apt-get install openjdk-11-jdkThis command installs OpenJDK 11, which is the latest LTS version at the time of writing. If you prefer a different version, replace openjdk-11-jdk with the version you prefer.
Compiling Java Programs
Once JDK is installed, you can compile your Java programs. Navigate to the directory where your Java program is located using the cd command. For instance, if your Java program (MyProgram.java) is located in the Documents directory, you would use:
cd DocumentsTo compile your Java program, use the javac command followed by the name of your Java file:
javac MyProgram.javaThe javac command is the Java compiler included in JDK. It takes a Java source file as input and outputs Java bytecode, which can be executed by the Java Virtual Machine (JVM).
If there are no compilation errors, this command will create a new file with the same name as your Java program but with a .class extension (MyProgram.class). This .class file contains the bytecode version of your program that can be interpreted by the JVM.
Running Java Programs
After successful compilation, you can run your Java program using the java command followed by the name of the class:
java MyProgramNote that you should exclude the .class extension when running the program. The java command launches the JVM and loads the class you specify, then executes its main method.
Conclusion
In this article, we have covered how to compile and run Java programs in Ubuntu. We installed the necessary JDK, compiled a Java program, and ran it using the JVM. With these steps, you should be able to run any Java program on your Ubuntu system. If you encounter any issues, make sure to check the error messages in the terminal as they often provide clues to the problem. Happy coding!
You can check if Java is installed on your Ubuntu system by using the java -version command in the terminal. This command will display the installed version of Java.
You can install Java on Ubuntu by following this guide: How To Install Java with Apt on Ubuntu 18.04. It provides step-by-step instructions on installing Java using the apt package manager.
JDK stands for Java Development Kit. It is a software development environment used for developing Java applications. JDK includes the Java Runtime Environment (JRE), a compiler (javac), an interpreter/loader (java), and other tools needed in Java development.
To compile a Java program in Ubuntu, navigate to the directory where your Java program is located using the cd command. Then, use the javac command followed by the name of your Java file. For example: javac MyProgram.java. This will create a .class file containing the bytecode version of your program.
After successful compilation, you can run a Java program in Ubuntu using the java command followed by the name of the class. For example: java MyProgram. Remember to exclude the .class extension when running the program.
If there are compilation errors, carefully review the error messages displayed in the terminal. They often provide clues to the problem. Check for syntax errors, missing dependencies, or incorrect file paths. Make the necessary corrections and try compiling again.
Yes, you can install and use a different version of Java on Ubuntu. Instead of openjdk-11-jdk, you can install a different version by replacing it with the desired version in the installation command. For example, to install OpenJDK 8, you would use sudo apt-get install openjdk-8-jdk.
