Step 5: Run the Java preview feature code With the code compiled, you can execute it by adding the --enable-preview switch to the java command: jdk13@preview:$ java --enable-preview ...

But these aforementioned Java command-line tools -- namely, javac, javap, jstat, jdeps and jar -- are the five that serious software developers need to know.

Learn how to use the Command pattern to encapsulate requests as objects that you can execute alone or in sequence in your Java programs.