HelloWorld.class contains the executable equivalent of HelloWorld.java. To run this class file via the java application launcher tool, execute the following command: ...

$ javac HelloWorld.java $ java HelloWorld The runner compiles the source in memory and executes the first main class it discovers.

2024 is a great time to start working with Java, because 2023's Java 21 release has some amazing new features. Here's how to quickly download and install the Java 21 JDK.