Polymorphism in Java
A polymorphic reference is a variable that can refer to different types of objects. A reference can refer to an object of its class, or to an object of any subclass. When we call a method through a polymorphic reference, …
Category: Java
Inheritance in Java
The following are different relationships between classes. Let A and B be two classes. Dependency: A uses B Aggregation: A has-a B (as an attribute) Inheritance: B is a kind of A Subclass and Superclass In Java, new classes (child …
Writing Classes in Java
There are two meanings of “class”. A class could be: a code library (a collection of methods). For example, java.lang.Math contains methods for performing basic numeric operations. an object data type (a description of a concept). For example, java.lang.String represents …
Read and Write Text Files in Java
An I/O Stream represents an input source or an output destination. A stream can represent many different kinds of sources and destinations, including disk files, devices, other programs, and memory arrays. A file is identified by its path through the …