Final answer:
The Bootstrap Class Loader is the parent class loader in Java that loads core JDK classes from the rt.jar file and other core libraries. It is written in native code, part of the JVM, and does not have a parent. This loader plays a critical role in maintaining Java runtime environment security and integrity.
Step-by-step explanation:
The Bootstrap Class Loader in Java is the parent class loader that loads the core Java classes provided by the JDK. It loads classes like java.lang.Object and other runtime classes that are found in the rt.jar file and other core libraries at the bootstrap class path. This class loader is part of the Java Virtual Machine (JVM) and is written in native code. It is the root of the class loader hierarchy in Java and does not have a parent. Other class loaders, such as the Extension Class Loader and the System/Application Class Loader, build upon the classes that the Bootstrap Class Loader loads.
The Bootstrap Class Loader is crucial for the Java runtime environment because it loads the fundamental classes necessary to run Java applications. It ensures that important security constraints are not violated and maintains the integrity of the Java core classes. As it is written in native code, not Java, it interacts closely with the underlying operating system.