It is a bit similar to a class. Semantically, structures are known as value types, while classes as reference types. We don’t instantiate an object using the New keyword while working with a structure. We can not inherit from a structure.
An Abstract class is a class with some common/certain implementations and defines abstraction for other services which are implemented in its concrete sub classes, whereas interface only have method declaration with zero implementations. The difference between Abstract class and An Interface is that if u call Abstract class then u… Continue reading
Shadowing is a concept of polymorphism usage in Object Oriented Programming. This is a concept related to over-riding functions at run-time or making a shadow of the object’s methods in the inherited classes. Though it is not much used in programming but it may be used sometimes and its usage… Continue reading
Private constructor is used if you do not want other classes to instantiate the object and to prevent subclassing. The instantiation is done by a public static method (i.e. a static factory method) within the same class. Used in the singleton design pattern. Used in the factory method design pattern… Continue reading
Modifier Used with Description public Outer classes, interfaces, constructors, Inner classes, methods and field variables A class or interface may be accessed from outside the package. Constructors, inner classes, methods and field variables may be accessed wherever their class is accessed. protected Constructors, inner classes, methods, and field variables. Accessed… Continue reading
Queue Stack First item to be inserted is the first one to be removed. Allows access to only last item inserted. This mechanism is called First In First Out (FIFO). An item is inserted or removed from one end called the “top” of the stack. This is called Last In… Continue reading
Vector / Hashtable ArrayList / HashMap Original classes before the introduction of Collections API. Vector & Hashtable are synchronized. Any method that touches their contents is thread-safe. So if you don’t need a thread safe collection, use the ArrayList or HashMap. Why pay the price of synchronization unnecessarily at the… Continue reading
For polymorphic interface inheritance, where the client wants to only deal with a type and does not care about the actual implementation use interfaces. If you need to change your design frequently, you should prefer using interface to abstract. Coding to an interface reduces coupling and interface inheritance can achieve… Continue reading
In case where you want to use implementation inheritance then it is usually provided by an abstract base class. Abstract classes are excellent candidates inside of application frameworks. Abstract classes let you define some default behavior and force subclasses to provide any specific behavior.
If you read the XP life cycle, one of the things after we implement the task is code refactoring. Refactoring is the process of changing the software in such a way that it does not change the behavior of the code but on the other hand improves the internal structure…. Continue reading