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Ready-made multiple-choice practice quizzes, hand-checked. Take any free quiz online — every answer comes with an explanation, and every quiz page has a full answer key to revise from.
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Free · no sign-up · no time limit
Ready-made multiple-choice practice quizzes, hand-checked. Take any free quiz online — every answer comes with an explanation, and every quiz page has a full answer key to revise from.
IT
Records, pattern matching, virtual threads, and more from the Java 21 LTS. Answer each question to see whether you got it right, with an explanation every time.
A free 6-question multiple-choice practice test on IT. Each question has one correct answer and a short explanation, and the full answer key below the player doubles as a study sheet. No account, no time limit — take it as often as you like.
This is a free, 6-question multiple-choice quiz. Answer each question to see whether you got it right, with an explanation for every answer. There is no sign-up and no time limit — take it as many times as you like, and use the answer key above to revise before or after.
Correct answer: BA Long-Term Support (LTS) release
Java 21 is an LTS release, like 17 and 11 before it.
Correct answer: BVirtual threads
JEP 444 finalizes virtual threads, lightweight threads managed by the JVM instead of the OS.
Correct answer: ADestructure a record directly in a pattern, e.g. in a switch or instanceof
Record patterns let you match and extract a record’s components in one step, e.g. `case Point(int x, int y) ->`.
Correct answer: ASequencedCollection
JEP 431 introduces `SequencedCollection`, `SequencedSet`, and `SequencedMap`, adding well-defined encounter order and first/last accessors.
Correct answer: CFinal (standard) feature
JEP 441 finalizes pattern matching for switch after several rounds of preview in earlier versions.
Correct answer: ALower memory usage per request and far higher concurrency without rewriting to async code
Virtual threads let you keep a simple one-thread-per-request style while scaling to huge numbers of concurrent blocked threads cheaply.