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

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

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 ...