we will help you to understand about Java OOP’S concepts with examples. oops concepts in java
The magic of super() We have seen earlier, the usage of this() statement where it is used to call in between the constructors belonging to the same class. Here no inheritance is involved. Now in this posting, let us learn how to call a super class constructor from subclass constructor. Example on super() class Animal …
In Java, both this and this() are entirely different with different functionalities. Functionalities (Purposes) this keyword is used to refer always current object this() is used to access one constructor from another where both constructors belong to the same class Following table illustrates the differences. this keyword this() Used with objects only Used with constructors …
Difference between this and this() in Java with Example Read More »
Method overloading and method overriding are two concepts supported by a OOPs language. Method overloading Definition: Using the same method number of times in the same class but with different parameters is known as method overloading. Advantages: The same method call gives different outputs when called different times. For example, getArea() method may give sometimes …
We know earlier what is a constructor, default constructor, types of constructors and their advantages and place in Java language. Let us know one more concept of constructors known as constructor overloading. Like method overloading, Java also supports constructor overloading. Writing multiple constructors, with different parameters, in the same class is known as constructor overloading. …
Java Tutorial: Constructor Overloading with Example Read More »
One of the simplest methodologies of learning a subject is through Questions/Answers. I believe in this. 17 questions with answers on Constructors Java are given. 1. What is constructor? 2. Define constructor in Java? 3. What is class constructor in Java? 4. What is the return of constructor? One of the Java constructs (with which …
Constructors Java: Learn through Questions and Answers Read More »
No, it is not possible. Designers did not provide a way. Of course, it is of common sense also. Because interface contains only abstract methods and as abstract methods do not have a body (of implementation code), we cannot create an object. Suppose even if it is permitted, what is the use. Calling the abstract …
Abstract class object: Put the same question for an interface. Everyone says anonymously, "no" because there is no implementation (body) of methods as all are abstract. But what about with abstract class? Coming to an abstract class, the question arises as one variation of abstract class is that it can contain all concrete methods. I …
Java Encapsulation : In an object-oriented programming language, Encapsulation, Abstraction, Data hiding and Data binding are very confusing words, everyone feels difficult to understand. Many Web sites discuss at length and finally one site contradicts slightly with the other with many user comments of what they feel. Here I give in my own style of …
Java Encapsulation Abstraction Data hiding and Data binding Read More »
Creating and using constructor along properties should paid more attention by the Programmer as Using Constructor is inevitable in everywhere in Java coding. Many postings are given with utmost importance about using constructor in way2java.com and read them as well as to get all the concepts in one example is not possible. In Java, a …
Java Hello World: Java is a simple language to practice. The code is very simple to understand and write. Many things which you are supposed to write are taken care implicitly by Java. But it takes sometime to you to accept. Now let us write a simple example "Java Hello World" and then discuss the …
Java constructor plays a very important role in coding. Simply a constructor looks like method but is very different from method and purpose. Following tutorial gives complete authority over Java constructors. First let us know where exactly constructors fit in Java coding. A constructor is that one which is called implicitly when an object is …
Calling Constructor from Constructor requires precautions on usage. Read and understand carefully. What is a constructor and what is its role in programming? A constructor is that one which is called implicitly when an object is created in Java. A constructor gives properties to an object while it is being created itself. Else, separate methods …
Static Method and Static Variable: In Java, static is keyword that can be applied to variables and methods but not to classes. static is used as an access modifier. In Java, to call an instance variable or method, an object is required. But a static variable and method can be called without the help of …
Aggregation and Composition are very closely related terms where a novice gets confused and some examples are of good debate too. Observe the code. class Test { public void display() { System.out.println(“Hello 1”); } } class Demo { public static void main(String args[]) { Test t1 = new Test(); t1.display(); } } We say, class …
Overloading and Overriding, are two terms very confusing for a for a Beginner learning Java. Read this, and say you are still confused. Both are supported by OOPS languages like Java and C++ but not by C-lang. To explain, I take it granted you know methods and inheritance in Java. At an outset, to know …
Access Specifier vs Access Modifier: For a novice, both the words specifier and modifier looks one and the same and may be confusing. If you go by the literal meaning, it is more confusing, say, an access specifier specifies the access and access modifier modifies the access. Of course, if the meaning and functionality is …
Java uses two keywords to inherit – extends and implements. The difference of them and their usage is trivial to understand. Introduction Java Extends vs Implements Go through the following combinations and rules one-by-one. Write small programs and practice. It is required to master them for a better Developer. 1. Inheritance between concrete (non-abstract) and …
Extends vs Implements: Once you know the basic structure of a Java class, know inheritance with concrete classes and abstract classes, know to inherit interfaces, it is the time for both extends and implements where you inherit classes and interfaces to one class. For example, you have two classes (one may be abstract and the …
In Java implements is a keyword. Where to use implements keyword in Java coding? We know Java does not support multiple inheritance. That is, one class cannot extend or inherit two classes. That is, following code does not work. class Bird { } class Animal { } public class Ostrich extends Bird, Animal { } …
In the earlier, Bird-Ostrich inheritance program, Ostrich extends only one class, Bird, because Ostrich wants to walk and the method is there in Bird’s class. Now Ostrich also wants to eat but the eat() method is there in another class Animal. Now, it is required to Ostrich to extend two classes Bird and Animal. Observe …
