What is the default initial capacity of an ArrayList in Java when instantiated using the default constructor?
Option B is correct. When created with new ArrayList<>(), Java assigns an initial internal buffer array capacity of 10 elements.
Which keyword in Java is used by a method to explicitly throw an exception object to the caller?
Option C is correct. The 'throw' keyword is used to explicitly raise an exception instance (e.g., throw new IllegalArgumentException()). 'throws' is used in method signatures.
What is the purpose of the 'volatile' modifier in Java?
Option B is correct. Volatile guarantees thread visibility of changes to variables across threads by forcing reads/writes directly to main RAM.
In Java Garbage Collection, which method can be called to request the JVM to run garbage collection (though execution is not guaranteed)?
Option C is correct. System.gc() sends a request to the JVM to perform memory cleanup, though execution timing remains at the JVM's discretion.
Which Map implementation in Java maintains keys in ascending sorted order using Natural Ordering or a custom Comparator?
Option C is correct. TreeMap is a Red-Black tree-based NavigableMap implementation that guarantees sorted key order.