Object-Oriented Programming

Case 1 (B to A) is upcasting - a subclass reference can always be assigned to a superclass reference, so it compiles and runs. Case 2 (A to B) is downcasting - requires explicit cast syntax B b=(B)a. With the cast it compiles but fails at runtime if 'a' doesn't actually reference a B object (ClassCastException). Without cast, it won't compile.

B is true because Object's finalize() is empty by default. D is true - GC guarantees finalize is called at most once per object. A is false - you CAN call finalize explicitly. C is false - super.finalize() must be called explicitly. E is false - finalization order is NOT guaranteed.

When an access role is specified at a parent class in Pega, it applies to that parent class AND all its child classes by default. However, if a child class has an explicit access rule that overrides the inherited role, the override takes precedence for that child class. This is inheritance with override capability.

In Pega, pattern inheritance searches for parent classes by truncating segments separated by dashes. For the class MICO-Finance-, removing the trailing dash and the last segment yields MICO-Finance (or case-normalized Mico-Finance) as its pattern parent.

Cover and Covered objects in PEGA must belong to the same ClassGroup to maintain proper object relationships. The Cover-Covered relationship links related work objects within the same class group hierarchy, allowing parent-child associations. AccessGroup and WorkPool control different aspects (security and work assignment) and don't determine cover relationships.

In PEGA, pz properties are system-protected read-only properties that cannot be modified by users or developers, ensuring system integrity. px and py properties can be modified under appropriate circumstances. The pz prefix specifically denotes protected system properties.

Ordinary work objects in PEGA inherit from the Work-Object- base class, which provides standard work object functionality. Covered work objects inherit from Work-Cover- class, not Cover-Object-. Folders can contain multiple covered objects, and folders themselves are organizational structures, not work objects.

When creating a class in Pega, Direct Inheritance is mandatory - every class must have a parent class specified through direct inheritance. Pattern Inheritance is optional and provides an additional inheritance mechanism based on naming patterns. A class cannot exist without specifying its direct parent.

Object and Math are fundamental classes in java.lang package. Object is the root class of all Java classes, and Math provides mathematical functions. Random is in java.util, and Stack is in java.util, not java.lang.

Abstract classes cannot be instantiated directly because they contain at least one pure virtual function with no implementation. You can only create objects of concrete derived classes that implement all the pure virtual functions. The abstract class serves as a template for inheritance.

Virtual functions in parent classes do NOT need to be redefined in all child classes. A child class can inherit the parent's implementation if it doesn't need custom behavior. The override is optional - it's only required if the child class needs specific behavior.

In object-oriented theory and most language implementations, every class is considered a trivial subclass of itself. The "is-a" relationship is reflexive - a class is itself. This is mathematically consistent with inheritance hierarchies and type systems.

this() is used in constructors to call another constructor of the same class (constructor chaining). It must be the first line in the constructor. This allows code reuse between overloaded constructors and avoids duplicating initialization logic.

Static constructors are invoked first when a class is initialized, before any instance constructor. They run once per type (not per object) to initialize static class members. The public constructor runs after the static constructor completes.