Compile Java Code From the Terminal

Apr 9, 2022

How to use any terminal to compile and run Java source code.

What You Need

Java Source Code

You will need to write your Java code and save it with the .java extension.

Java Compiler

To check if you have one type javac --version into the terminal. Also, check that the version of javac and that of java --version are identical. If not you may get the following error:

Error: A JNI error has occurred, please check your installation and try again Exception in
 thread "main" java.lang.UnsupportedClassVersionError: MyList has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java
  Runtime only recognizes class file versions up to 52.0

Use sudo update-alternatives --config java to pick the correct version.

Steps to Compile and Run the code

1. Open a terminal in the same directory as your .java file.

2. Type javac filename.java, this will generate .class files.

3. Type java filename (without extension), this should run your code.