How to use the Java Interview Flashcards
- 1. Choose topicsPick one topic or all of them, a round size, and whether to skip cards you already know.
- 2. Flip and gradeRead the question, answer aloud, then reveal the answer and mark it known or still learning.
- 3. Review your resultsMissed cards come back later in the round. At the end see your score by topic and download the cards to revise.
What the deck covers
This deck covers the core Java questions that come up in fresher and junior developer interviews, from JDK vs JVM to streams and Optional. The 25 cards are grouped into 9 topics: Basics, Strings, OOP, Keywords, Collections, Exceptions, Memory, Concurrency, Java 8+. Answers are short on purpose: one or two sentences you can say out loud, which you then back up with an example from your own projects.
A card from the deck
Q: How does HashMap work internally?
A: It stores entries in an array of buckets. The key's hashCode() picks a bucket; collisions are kept in a list, which becomes a balanced tree when a bucket grows large (Java 8+). equals() finds the exact key. The table resizes when it passes its load factor (0.75).
This is one of the most common follow-up questions after "what is a HashMap?". A strong answer also mentions what happens if two keys have the same hash code and why equals() matters.
How to study with it
- Explain each answer aloud before flipping; interviews test how clearly you say it, not just whether you know it.
- For OOP cards, prepare one example from your own code for each pillar.
- In the Java deck, cards you mark "still learning" come back three cards later in the same round, and the results screen lists them so you can download a revision sheet.
More questions from this deck
Other Java questions you'll meet include:
- Why is Java called platform independent?
- What are the four pillars of OOP?
- Can a constructor be private? Why would you do that?
- Checked vs unchecked exceptions?
- What are streams used for?
Frequently asked questions
Which Java version do the answers follow?
Modern Java (8 to 21). Older behaviour is mentioned where it matters, such as HashMap buckets becoming trees in Java 8.
Is this enough for a Java interview?
It's a revision aid. Also practise coding problems and be ready to discuss your projects.
Are the Java interview flashcards free?
Yes. You can flip through every card of the Java interview flashcards without signing up. When you open your results for the first time, we ask once for your name and WhatsApp number; after that the Java interview flashcards and every other Uncodemy tool open straight away.