Development Environment Set Up: Java

Recommended completion before Monday's class but definitely before Wednesday's class

Objective

To get your development environment set up for Java.

Installing Java's Development Kit

If you plan to work only on the lab machines, you can skip this step, but it's probably helpful to have Java installed on your personal machine(s).

We will be using the newest long-term support (LTS) version of Java: 21. Specifically, I recommend that you get Liberica, a free, supported, 100% open-source OpenJDK. Make sure you get the JDK (which includes the JRE), not only the JRE. Also, make sure you get the version that is appropriate for your machine's processor.

After installing, on the command line, confirm that you're using Java 21 by running
java -version
javac -version
and seeing that the version is 21.

If you had previously installed Java, you may see an older version number. While that likely won't be a problem with the level of code we'll be writing, I'd prefer to avoid any issues.

• For Windows -- adapt instructions for jdk-21
• For Mac -- adapt instructions for jdk-21

If you get an error that says something about "Bad CPU", make sure you have installed the version that is appropriate for your machine's processor.

Check Java Development Environment

After Monday's class but before Wednesday's class

• Create a new directory within the directory that you're using for this class, e.g., practice
• Download First.java and save it in your practice directory.
• In your terminal, navigate to your practice directory.
• Compile and run First.java:
  • javac First.java
    Compiles the program into First.class
    List the contents of your directory to see First.class
  • java First
    Runs the JVM, which executes the bytecode
• View First.java in your favorite text editor, e.g., if your text editor is jEdit, you'd run
  jedit First.java &.
• Review the components of the program. Make sure you understand why the code outputs what it does.

Submitting your assignment

No submission. This is just on your honor that you do it, so you're ready for future work.