Practice Java SE 21 language and platform reasoning in a timed test. You have 120 minutes for 50 questions. Single-answer questions use round controls; questions with several correct answers use square controls and state the selection count. Read each snippet as Java SE 21 on a full JDK unless the question names the browser workspace. Some questions ask whether code compiles. Others ask for a value or a design consequence.
You can move between questions and flag one for another look. The clock continues if you reload the page. Submit when you finish, or let the clock submit your saved selections. The review explains the correct choices. These questions are original practice material, with no connection to Oracle exam content or an official certification score.