Java Tutorial

Java Tutorial Java Features C++ vs Java Java History Java Hello World Java Development Kit Java Runtime Environment Java Virtual Machine Difference between JDK, JRE, and JVM Memory Areas in Java Java Operators Java Keywords Primitive Data Types Variables

Java Loops

Java Do While Loop Java While Loop Java For Loop Java Enhanced For Loop

Java Programs

Java Basic Programs Factorial Program in Java Fibonacci Series Program in Java Prime Number Program in Java Palindrome Number Program in Java Armstrong Number Program in Java Anagram Program in Java Pattern Programs in Java Calculator Program in Java Leap Year Program in Java Addition Program in Java Number Pattern Programs in Java Star Pattern Programs in Java Package Program in Java Pyramid Program in Java Sorting Program in Java String Palindrome Program in Java Even Odd Program in Java For Loop Program in Java If Else Program in Java Switch Case Program in Java GCD Program in Java LCM Program in Java Hello Program in Java Matrix Program in Java Menu Driven Program in Java Series Program in Java Client Server Program in Java Swapping Program in Java Pig Latin Program in Java Tower of Hanoi Program in Java Recursion Program in Java Matrix Multiplication Program in Java Perfect Number Program in Java Classes and Objects in Java Example Programs String Programs in Java Array Programs in Java Constructor Program in Java Inheritance Program in Java Abstract class Program in Java Interface Program in Java Encapsulation Program in Java Polymorphism Program in Java Exception Handling Program in Java Multithreading Program in Java Thread Program in Java Collection Programs in Java ArrayList Program in Java Stack Program in Java Applet Program in Java Swing Program in Java JDBC Program in Java How to run Java program in command prompt How to run Java program in Eclipse

Java Sorting

Sorting Algorithms in Java Merge Sort in Java Quick Sort in Java Bubble Sort in Java Insertion Sort in Java Selection Sort in Java Heap Sort in Java Radix Sort in Java Topological Sort in Java Bucket Sort in Java Counting Sort in Java

Java OOPs Concepts

OOPs - Object Oriented Programming Objects and Classes in Java Java Naming Conventions Constructors in Java Java this keyword Java static keyword Inheritance in Java Aggregation in Java Java super keyword Constructor Chaining and Constructor Overloading Java Polymorphism Static and Dynamic Binding in Java Java Abstraction Abstract class in Java Interface in Java Difference between Abstract class and Interface Java final keyword Packages in Java Access Modifiers in Java Java Wrapper classes Java Numbers Java Characters Java Integer Java Boolean Java Arrays Java Command Line Arguments Java strictfp Keyword Java Math

Java Strings

Java Strings Java String Methods StringBuilder in Java StringBuffer in Java Java Regular Expressions StringBuffer vs StringBuilder String vs StringBuffer String vs StringBuilder String Manipulation in Java Java String Concatenation How to Reverse a String in Java String Array in Java How to Compare Two Strings in Java How to Concatenate Two Strings in Java Why String in Immutable in Java java.lang.NumberFormatException for Input String String Pool in Java Java Generate Random String How to take String Input in Java Java String Interview Questions

Java Exceptions

Exception Handling in Java Java try catch Java throw Java throws Difference between throw and throws Java finally Java Custom Exception Java Exception Propagation

Garbage Collection

Automatic Resource Management in Java Java Garbage Collection Java finalize() Java gc() Difference between final, finally and finalize

Multithreading

Multithreading in Java Process and Thread in Java Basic Terms in Multithreading Java Thread creation Thread Scheduler in Java Java Thread class DeadLock in Java

Java IO

Java IO Java Read File Java BufferedWriter Java InputStreamReader Java File Java Read File Line By Line Java FileOutputStream Jar File in Java

Serialization

Java Serialization Java transient

Networking

Java Network Programming Java Socket Programming Java URL Java URLConnection HttpURLConnection in Java Java InetAddress Java DatagramSocket and Java DatagramPacket

AWT

Java AWT

Swing

Swing in Java

Java Collections

Collections in Java Java List Interface ArrayList in Java LinkedList in Java Vector in Java Stack in Java ArrayList vs LinkedList in Java ArrayList vs Vector in Java Java Set Interface HashSet in Java LinkedHashSet in Java TreeSet in Java Java Queue Interface PriorityQueue in Java ArrayDeque in Java Java Map Interface HashMap in Java LinkedHashMap in Java TreeMap in Java Dictionary in Java Hashtable in Java Properties in Java Collections class in Java Java Comparable Java Comparator Comparable vs Comparator in Java

Java Generics

Generics in Java

Java Annotations

Annotations in Java

Java JDBC

Java JDBC Tutorial

Java Differences

Java vs JavaScript Python vs Java Kotlin vs Java Java vs C++ C# vs Java Static vs Non-static in Java C vs Java int vs Integer in Java Stack vs Heap in Java Java Array vs ArrayList

How to

How to run Java program How to set path in Java How to check the Java version in cmd How to install Java in Windows 10 How to run Java program in cmd How to call a method in Java How to sort an array in Java How to iterate HashMap in Java How to write Java program How to create an array in Java How to create a package in Java How to generate random numbers in Java How to input String in Java How to create thread in Java How to find length of String in Java How to sort a string in Java How to use scanner in Java How to achieve multiple inheritance in Java How to run Java program in Eclipse How to call a function in Java How to create array of objects in Java How to create custom exception in Java How to achieve abstraction in Java How to call static method in Java

Java 8 Features

Java 8 Features Lambda Expressions in Java Functional Interface in Java Streams in Java Java Base64 Encoding and Decoding Parallel Arrays Sort in Java

Java 9 Features

Java 9 Tutorial Java 9 Try With Resources Java 9 Interface Private Method

Java Servlet Tutorial

Java Servlets Tutorial

Java JSP Tutorial

Java JSP Tutorial

Hibernate Tutorial

Hibernate Tutorial

Spring Tutorial

Spring Tutorial

Spring MVC Tutorial

Spring MVC Tutorial

Jenkins Tutorial

Jenkins Tutorial

Java Math Methods

Math.abs() Math.acos() Math.addExact() Math.asin() Math.atan () Math.atan2() Math.cbrt() Math.ceil() Math.copysign() Math.cos() Math.cosh() Math.decrementExact() Math.exp() Math.expm1() Math.floor() Math.floorDiv() Math.floorMod() Math.getExponent() Math.hypot() Math.IEEEremainder() Math.incrementExact() Math.log() Math.log10() Math.log1p() Math.max() Math.min() Math.multiplyExact() Math.multiplyFull() Math.negateExact() Math.nextAfter() Math.nextDown() Math.nextUp() Math.pow() Math.random() Math.rint() Math.round() Math.scalb() Math.signum() Math.sin() Math.sinh() Math.sqrt() Math.subtractExact() Math.tan() Math.tanh() Math.toDegrees() Math.toIntExact() Math.toRadians() Math.ulp()

Java String Methods

toCharArray() copyValueOf() endsWith() equals() equalsIgnoreCase() format() getBytes() getChars() hashCode() indexOf() intern() isEmpty() join() lastIndexOf() length() replace() replaceAll() replaceFirst() split() startsWith() subSequence() substring() toLowerCase() toUpperCase() trim() valueOf()

Java Conversion

Java Convert String to int Java Convert int to String Java Convert String to long Java Convert long to String Java Convert String to float Java Convert float to String Java Convert String to double Java Convert double to String Java Convert String to Date Java Convert Date to String Java Convert String to Object Java Convert Object to String Java Convert String to char Java Convert char to String Java Convert int to long Java Convert long to int

Misc

Functional Interfaces in Java Singleton class in Java Awesome explanation of Strings in Java Object class in Java Static class in Java All the important string methods in Java String Handling Method in Java What are Array strings in Java Advantages and Disadvantages of Strings in Java Big Decimal class in Java Class definition in Java Char and String differences in Java Difference between String, StringBuffer and StringBuilder in java Replace character in string Java String Coding Interview Questions in Java What is String in Java? String isnullorempty in Java String Matches in Java Trim Method in String Java Bean class in Java Libraries in Java Arithmetic Operations on String in Java

Java Abstraction

Java Abstraction Abstraction is an advanced feature of Java to make it transparent. The main motive behind the abstraction is to deal with ideas, not with events. Abstraction is a process for hiding the implementation details from the user. Java developers can only provide the functionality to the user and hide the implementation detail using abstraction. Abstraction is one of the most important features of oops. It is achieved using abstract classes and interfaces. Java uses a keyword 'abstract’ to make a class abstract. Suppose a user is making a call to another user. He is simply enjoying the service, but he has no idea about the functionality of how things are working, this is called an Abstraction. Let's understand it with a programming example. Suppose you are making a banking application and you are asked to collect all the information of the customer. Then there is a chance that you will come up with some additional info about the user like favorite movie, favorite Actor, but all these information are not necessary to create an application. So you need to select only the useful information for your project from that collection of data. Since we can fetch/ remove/ select the information from that collection of data, this process is referred to Abstraction.

How to achieve Abstraction in Java?

There is two way to achieve abstraction in Java.
  • Java Abstract classes (0 to 100%)
  • Java Interfaces (100%)
Example This is an example of Java Abstraction.
abstract class Fortuner{
abstract void speed();
}
class Car extends Fortuner{
void speed(){
System.out.println("Speed is 220 km/h");}
public static void main(String args[]){
Fortuner obj=new Car();
obj.speed();
}
Output
Speed is 220 km/h
Above example describes that how the abstraction achieved in java. Class Fortuner and method speed() is abstracted in the given example.

Java Abstract classes

An Abstract class is a class that contains abstract as well as concrete methods. A class is created Abstract using the keyword 'abstract’. An Abstract class can't be instantiated, in other words. We cannot create the object of an abstract class. Abstract class can have both abstract and concrete methods. abstract class Account{ public abstract void debit(); public void credit() { System.out.println(“Account Statement”)}} If we create the object of the given class Account then it will produce an error. Account obj=new Account(); //it will produce an error To use the abstract class, we must inherit it from the other class. Abstract methods in abstract class do not have a body. We can achieve 0 to 100 percent abstraction using Java abstract classes. See the Example below
//Abstract class
abstract class Transaction {
public abstract void credit();
public void debit() {
 System.out.println("Account is debited");
}
}
//Subclass (inherit from Transaction)
class Account extends Transaction{
public void credit() {
 // The body of credit() is provided here
 System.out.println("Account is credited");
}
public static void main(String[] args) {
 Account obj = new Account();
 obj.credit();
 obj.debit();
}
}
Output
Account is credited
Account is debited

Java Interface

Java interface is a collection of abstract methods and static constants. It’s like a class that contains only static constants and abstract methods. We can achieve 100 % abstraction using Interfaces. The interface does not contain any constructors. Methods in an interface are only public and abstract. The interface is responsible for what a class will do; it is like a blueprint of the class.  Java uses interfaces to achieve multiple inheritances. To use an interface in a class, use the keyword implements after the interface name. Java class can implement more than one interface (multiple interfaces). Let's take a tour with the following examples to understand the implementation of the interface. Example 1 This is a format of the interface.
public interface InterfaceName {
public String hello = "Hello";
public void sayHello();
}
As you can see at the given example, an interface is declared using the interface keyword. Just like with classes, a Java interface can be declared public or package scope; it does not use access specifier. The above example contains one variable and one method. In Java, the variable can be accessed directly from the interface, like this:
System.out.println(InterfaceName.hello);
Example 2
interface X
{
void m1();
void m2();
void m3();
void m4();}
abstract class Test2 implements X{
public void m3()
{
     System.out.println("In method m3");
     }}
class Test3 extends Test2{
public void m1(){System.out.println("In method m1");}
public void m2(){System.out.println("In method m2");}
public void m4(){ System.out.println("In method m4");
}}
public class Test1{
public static void main(String args[]){
X obj=new Test3();
obj.m1();
obj.m2();
obj.m3();
obj.m4();}
}
Output
In method m1
In method m2
In method m3
In method m4

Advantage of Abstraction

Some of the advantages of abstraction are as follows
  • It reduces view complexity of the class members.
  • It avoids duplication of code.
  • It increases the reusability of code.
  • It Increases the readability of the program if things are appropriately abstracted, then the reader does not retain everything.
  • It supports polymorphism.
  • It provides security.

Abstraction VS. Encapsulation

Both abstraction and interface are a major oops concept of Java. They allowed you to enhance the real world thing into an object so it can be implemented in the program. Many are got confused between abstraction and encapsulation because they are quite similar. Abstraction hides complexity while encapsulation hides internal working. Let’s have a look at some following differences.
1 Abstraction hides details at the design level. Encapsulation hides details at the implementation level.
2 Abstraction hides unwanted information for the user's dynamic view. Encapsulation hides the block of code. Wrap it into a single unit.
3 It uses the keyword abstract to make an abstract class for abstraction In encapsulation create a class variable as private.
4 Abstraction is created using abstract classes and interfaces. Provides setter and getter for accessing and modifying the data.
5 Abstraction is used for hiding the backend data. It wraps up data into a single unit.
 



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