What is the memory area in Java Virtual Machine (JVM) architecture where class metadata, method data, and static fields are stored since Java 8?
Option C is correct. In Java 8, PermGen was removed and replaced by Metaspace, which is allocated out of native OS memory and dynamically resizes.
Which Garbage Collection algorithm in modern HotSpot JVM divides the heap into equal-sized regions and performs concurrent marking and compaction?
Option B is correct. The G1 GC divides heap memory into contiguous regions and targets regions with the most garbage first to achieve high throughput with predictable pause times.
Which class loader in the JVM delegation hierarchy is responsible for loading core Java runtime classes from the java.base module (e.g., java.lang.Object)?
Option C is correct. The Bootstrap ClassLoader is the parent of all class loaders, implemented in native code, which loads core Java platform classes.
In Java 8, what container object is used to represent the presence or absence of a non-null value, helping to prevent explicit null checks and NPEs?
Option A is correct. Optional<T> is a single-value container that either contains a non-null value or is empty, encouraging explicit handling of missing values.
In Java 8, which syntax is used to refer to an existing method of a class or object without executing it (e.g., System.out::println)?
Option C is correct. Method References using the '::' double colon operator provide readable, compact syntax to refer directly to existing methods or constructors.