D286 Java Fundamentals - Set 2 - Part 3

Correct Answer: Execution falls through into subsequent cases

Without break, execution continues into the following case labels. This fall-through is occasionally intentional but is a frequent source of bugs.

Correct Answer: condition ? valueIfTrue : valueIfFalse

The ternary operator evaluates a boolean condition and yields the first value when true and the second when false, providing a concise alternative to a short if-else.

Correct Answer: A class declared within another class

A nested class is declared inside another class, used to logically group classes that are only relevant to their enclosing class and to increase encapsulation.

Correct Answer: Testing whether an object is an instance of a particular type

The instanceof operator returns true when the object reference is an instance of the specified class or interface, commonly checked before casting.

Correct Answer: An error from casting an object to an incompatible type

ClassCastException is thrown at runtime when code attempts to cast an object reference to a type of which it is not actually an instance.

Correct Answer: Automatic reclamation of memory from objects no longer reachable

The garbage collector automatically frees memory occupied by objects that are no longer reachable from any live reference, removing the need for manual deallocation.

Correct Answer: No, System.gc() is only a suggestion to the JVM

System.gc() merely suggests that the JVM perform collection. The JVM decides when collection actually occurs, so it cannot be forced deterministically.

Correct Answer: Adding content to the end of the builder's character sequence

StringBuilder.append() adds text to the end of its internal mutable buffer, avoiding the object creation overhead of repeated String concatenation.

Correct Answer: Defining a natural ordering so objects can be sorted

Implementing Comparable and its compareTo() method defines a natural ordering, allowing collections of the type to be sorted automatically.

Correct Answer: Generating API documentation from structured source comments

Javadoc comments beginning with /** and using tags such as @param and @return are processed into browsable HTML API documentation.