Week 60 — What is an array and how can one access its elements?

Week 59 — What are libraries in the context of Java and how can they be used in Java programs?

Week 58 — What is the "identity hash code" and how does it differ from other `hashCode()`s?

Week 57 — What is special about the `toString` method?

Week 56 — What is the unnamed package and what is special about it?

Week 55 — What is JUnit and what is it used for?

Week 54 — What is a functional interface?

Week 53 — What is `java.nio.file.Files` and how does it simplify I/O?

Week 52 — How can one interrupt threads (in Java) and why is that useful?

Week 51 — What is `Iterable` and how does it relate to for-each/enhanced `for` loops?

Week 50 — What is an `Executor` (from `java.util.concurrent`) and how can it be used?

Week 49 — What is `BigInteger` and `BigDecimal`?

Week 48 — What are `Stream`s (from `java.util.stream`) and how can they process data?

Week 47 — What is a switch expression and how is it different from switch statements?

Week 46 — What does the `static` keyword do in Java?

Week 45 — What's the purpose of the `InputStream` and `OutputStream` classes?

Week 44 — What does "type erasure" refer to?

Week 43 — What is a virtual thread and how is it different from a platform thread?

Week 42 — What is a `sealed` class or interface?

Week 41 — What is the purpose of the `Error` class and how is it different from `Exception`?