D286 Java Fundamentals - Set 4 - Part 3

Correct Answer: It returns a value and avoids accidental fall-through

Switch expressions using the arrow form return a value directly and do not fall through between cases, eliminating a longstanding source of bugs.

Correct Answer: A concise class for immutable data carriers with generated methods

A record concisely declares an immutable data carrier, with the compiler generating the constructor, accessors, equals(), hashCode(), and toString().

Correct Answer: Letting the compiler infer a local variable's type

The var keyword enables local variable type inference. The variable remains strongly and statically typed; only the explicit declaration is omitted.

Correct Answer: Unbounded recursion without a reachable base case

Each method call consumes stack space. Recursion that never reaches its base case exhausts the stack and triggers StackOverflowError.

Correct Answer: The heap being exhausted, often by retaining too many objects

OutOfMemoryError occurs when the JVM cannot allocate memory, commonly due to memory leaks where unneeded objects remain reachable and uncollectable.

Correct Answer: Unneeded objects remaining reachable so they are never collected

Even with garbage collection, objects that remain referenced, such as entries never removed from a long-lived collection, cannot be reclaimed and accumulate over time.

Correct Answer: Automating verification that code units behave as expected

JUnit provides annotations and assertions for writing automated tests that verify individual units of code, enabling rapid regression detection.

Correct Answer: That an actual result matches the expected result

An assertion compares the actual outcome against the expected value and fails the test when they differ, defining the test's pass criteria.

Correct Answer: It clarifies requirements and catches defects immediately

Writing tests early forces clear thinking about expected behavior and surfaces defects as soon as they are introduced, when they are cheapest to fix.

Correct Answer: Writing clear, well-named, small units with consistent structure

Clear naming, small focused units, and consistent structure make code understandable to the next reader, which is the dominant cost factor over a system's lifetime.