winkle
Test library
Technical Includes code

JavaStaff level.

Tests them on system-level Java — service boundaries, performance under load, and diagnosing a JVM that is misbehaving.

What's included

  • Only reviewed, approved questions
  • Every question editable before it’s sent
  • Timed at 35 minutes
  • Camera, screen and microphone recording
  • Leaving the tab is logged
  • Copy and paste blocked
  • Scored automatically, with reasons for written answers

What the 216 questions ask.

  • Multiple choice

    One right answer or several. Marked the moment they submit.

  • Code reading

    A snippet and one question: what does it do? Reading code, not just writing it.

Drawn from 58 topics

How many approved Staff questions the bank holds on each.

  • Java upgrades12
  • Executors10
  • Streams10
  • Start-up time8
  • Container sizing7
  • Modules7
  • Observability7
  • Supply-chain security7
  • Timeouts & cancellation7
  • Virtual threads7
  • Binary compatibility6
  • Caching6
  • Profiling tools6
  • Spring Boot upgrades6
  • Testing strategy6
  • Exceptions5
  • Garbage collection5
  • API evolution4
  • Backpressure4
  • Boxing costs4
  • Build tools4
  • Maps4
  • Structured concurrency4
  • Benchmarking3
  • HashMap internals3
  • Immutability3
  • Java memory model3
  • JIT & warm-up3
  • Lists3
  • Locks3
  • Memory leaks3
  • Object methods3
  • Records3
  • Sorting3
  • Spring Data JPA3
  • Collection complexity2
  • Comparators2
  • Generics2
  • Interfaces2
  • Maven2
  • Memory errors2
  • Memory model2
  • Sealed types2
  • Sets2
  • Synchronizers2
  • Transactions2
  • CompletableFuture1
  • Concurrency1
  • Deadlocks1
  • Enums1
  • Gradle1
  • Immutability & API design1
  • JVM & class loading1
  • Null safety1
  • Optional1
  • Serialization1
  • Strings1
  • Thread safety1

From test to shortlist in three steps.

  1. 01

    Pick a test

    Choose the skill and the level. Every question can be edited or swapped before anything is sent.

  2. 02

    Send one link

    Candidates take it in the browser from one link, against the clock.

  3. 03

    Read the scores

    Multiple choice marks itself. Written answers get a score with the reasoning behind it, so a surprising number can be checked.

About the Java test.

What employers ask before sending the Staff Java test, answered with its real figures.

  • How long does the Staff Java test take?

    20 questions in about 35 minutes. The clock is set to 35 minutes by default. Switch timing off in the test’s settings and the duration becomes a suggestion instead of a limit.

  • What kinds of questions are in it?

    It mixes multiple choice and code reading questions. Coding questions are answered in a code editor in the browser. Its questions run from intro to expert difficulty.

  • How is it scored?

    Automatically. Multiple choice marks itself the moment the candidate submits. Written answers are scored against a model answer, with partial credit for an answer that is partly right, and every written score comes with the reasoning behind it so a surprising one can be checked.

  • Which Java level should I send?

    Java comes at 4 levels: Junior (20 questions, 35 min), Mid (20 questions, 60 min), Senior (20 questions, 35 min) and Staff (20 questions, 35 min). Junior draws on introductory questions, Mid draws on intermediate questions, Senior draws on advanced questions and Staff draws on expert questions. Pick the level the role needs, not the one on the candidate’s CV.

  • Can I change the questions?

    Yes. Using a test puts a draft in your account, and you can edit, remove or swap any question before it goes to anyone.

  • How do you keep every result fair and honest?

    New tests start with camera, screen and microphone recording on, every time the candidate leaves the test tab logged, copy and paste blocked outside the code editor and questions hidden while the window isn’t in front, and printing blocked. Each is a switch in the test’s settings. You can also set how many times a candidate may leave the tab before the test submits itself, and shuffle the question order and answer options for each candidate.

  • Why can’t I see the questions on this page?

    A public page with the questions on it is an answer key for every candidate who finds it. Sign up free and using the test puts every question in front of you to review before anything is sent.

  • What does it cost?

    Nothing to start: sign up free, with no card. The plans and their limits are on the pricing page.

Send it today.

Sign up, and this test is waiting in your library, one click from a link you can send.