Rkavindu

Operators in java:-      Java operators are symbols that perform operations on variables and values. They are used to manipulate data and perform various computations in a Java program.     There are several types in java operators. Some of them are, Arithmetic operators. Relational operators. Logical operators. Bitwise operators. Assignment operators. Arithmetic operators:- Addition (+) : Adds two operands. Subtraction (-) : Subtracts the right operand from the left operand. Multiplication (*) : Multiplies two operands. Division (/) : Divides the left operand by the right operand. Modulus (%) : Returns the remainder of the division of the left operand by the right operand. Relational operators:- Equal to (==) : Checks if two operands are equal. Not equal to (!=) : Checks if two operands are not equal. Greater than ...

       Encapsulation is the process of organizing data into a single unit. It is the connection point between the code and the data it works with. Encapsulation can instead be understood as a protective shield that keeps code outside of it from accessing the data.      Its look like a real world capsule. In a real world capsule, we store medicine as a one unit. In java programming , we store data as a one unit for protecting the data. Access Modifiers:-      We use some access modifiers for data security. public -   Members of the public are accessible from any class, regardless of whether it is part of the same package or not. The Private Access Modifier is the most secure. private - Members (fields or methods) declared as private are only accessible within the same class. default - Members with default access are accessible within the same package but not outside of it. protected -  Protected members are accessible with...

 Java Interface      We use interface keyword for creating java interfaces. An Interface in Java programming language is defined as an abstract type used to specify the behavior of a class.     Interface is look like a class. Its runs like normal class. But we cant create objects to the interface. We can create object using upcasting . Old days we cant create constructors for interface. But nowadays we can create constructors for interface(After java 8).     We can create meaningless methods(abstract method) in interface for overriding. After java 8, we can hold normal methods also in interface.     In a interface can not have normal variables (int a=5). But in a interface can have variables using static( can access without creating objects)   and final( cannot change values after assigning)    type(static final int a=10 , static final String a="name").After java 8, we can have normal variables also.     We ...

 Java Abstraction      In Java, abstraction is the practice of keeping a code's implementation details hidden and just providing the user with the information they need to know. It offers the capacity to reduce complexity and ignore unimportant information in order to simplify complex systems.      Modifying a class or a method using the abstract keyword can also be called abstraction. Abstract methods:- abstract   keyword is used to declare the method as abstract. You have to place the  abstract   keyword before the method name in the method declaration. An abstract method contains a method signature, but no method body(meaningless method).  Abstract classes:- if a class has at least one abstract method, then the class must be declarer  as abstract class. You have to place the  abstract   keyword before the class name in the class declaration. Java abstract classes may or may not contain abstract methods. Cannot be f...

Java Polymorphism            Before starting this blog topic, first we want to know about some other things in java.    Overriding  Casting               You can get basic knowledge about that things using bellow blogger links. overriding        casting            Polymorphism:-      After overriding a method of a parent class to the child class, the process of upcasting and calling a method of the child class through a parent class reference is called as polymorphism.      Method Overloading allows a class to have multiple methods with the same name but different parameters (number, type, or order).      Types of polymorphism:- Compile-time polymorphism- It is also known as static polymorphism. This type of polymorphism is achieved by method overloading or operator overloading. Java does not support op...

Java Upcasting and Downcasting    1.Upcasting :-      The process of assigning an object from the subclass to the variable from the superclass reference can be called upcasting. In upcasting child class will runs always.      To put it another way, it's a method of handling a child class object as if it belonged to its parent class. The Java Virtual Machine (JVM) does this conversion implicitly during runtime.      The child class object loses its unique properties and methods that are absent from its parent class when upcasting is done. The methods and properties declared in the parent class are the only ones that the resultant object can access.      When you wish to refer to objects of multiple child classes using a single reference type, upcasting comes in handy. As a result, you can build more generic code that works with a variety of object kinds without needing to write unique code for each kind. 2.Downcasting ...