Java Tutorial Index

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 Program to find and replace characters on string in java Program to find the duplicate characters in a string Program to check whether a given character is present in a string or not Java Program to Print Permutations of String Java program to find frequency of characters in a string Java Program to remove duplicate characters in a string

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 Methods 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 file Reader Java Buffer Reader Java file Writer Java BufferedWriter Java InputStreamReader Scanner in Java Java StringReader Java StringReader Class Java StringWriter Class Java PrintWriter Java File Java Read File Line By Line Java FileInputStream Java FileOutputStream Java Create File Java Delete File Java Open File Java Read File to String Java copy file Jar File in Java Java FileNotFoundException

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 Deque 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 JDBC Architecture Types of JDBC Drivers JDBC vs ODBC Java Database Connectivity with MySQL Java Database Connectivity with Oracle Statements in java Prepared statement in Java Resultset in java Java ResultSetMetaData DatabaseMetaData in Java Callable Statement in Java Transaction Management in Java Design of JDBC

Java Differences

Java vs DotNET Java vs JavaScript Python vs Java Kotlin vs Java Java vs C++ C# vs Java Java float vs double Java vs Scala Java vs Go Java vs Golang Java Extends vs Implements Java vs Node.js Static vs Non-static in Java C vs Java int vs Integer in Java Java protected vs private Java vs Dot Net Stack vs Heap in Java Java Array vs ArrayList Java SE vs EE Class vs Object in Java Java vs Bedrock Difference between = = and equals ( ) in java Difference between C, C++, java HashMap Vs HashTable Checked vs Unchecked Exceptions in Java Difference between print() and println() in Java Differences between Lock and Monitor in Java Concurrency Differences between Set and List in Java How to calculate time difference in Java Char and String differences in Java Difference between String, StringBuffer and StringBuilder in java Difference between String and Char Array in Java Differences between Byte Code and Machine Code Difference between String Tokenizer and split Method in Java Difference between JIT and JVM in Java Difference Between Data Hiding and Abstraction in Java Difference between String Tokenizer and Split Method in Java Difference Between BufferedReader and FileReader Difference Between Thread.start() and Thread.run()

How to

How to convert String to String array in Java How to find length of integer in Java How to get Day Name from Date in Java How to open the Java control panel How to resolve Illegal state exceptions in Java How to reverse a linked list in java How to encrypt password in Java How to calculate time complexity of any program in Java How to check version of java in Linux How to enable java in chrome 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 add double quotes in a string in Java How to convert list to String in Java How to call a method in Java How to Set Environment Variables for Java How to sort an array in Java How to Create Immutable Classes 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 Singleton Class 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 find the length of an Array in Java How to Read Java JSON file 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 import packages in Java How to run applet Program in Java How to take Array Input in Java How to achieve abstraction in Java How to call static method in Java How to compare characters in Java How to compare dates in Java How to create a linked list in Java How to download Eclipse for Java How to get ASCII value of char in Java How to get the current date and time in Java How to handle NullPointerException in Java How to initialize string array in Java How to Install Java on MAC How to run java program in ubuntu How to find characters with the maximum number of times in a string java How to Set Java_home in Linux How to Split the String in Java with Delimiter How to take Multiple String Input in Java using Scanner class How to uninstall the Java in Ubuntu How to Update Java How to add Elements in Array in Java How to avoid deadlock in java How to Split String by Comma in Java How to remove special characters from String in Java How to remove last character from String in Java How to Read XML Files in Java How to download and install Eclipse in Windows How to Create an API in Java How to Round Double Float up to Two Decimal Places in Java How to create a mirror image of a 2D array in Java How to set timer in Java

Java 8 Features

Java 8 Features Lambda Expressions in Java Functional Interface in Java Streams in Java Java Base64 Encoding and Decoding Type Annotations in Java Java Stringjoiner Class Parallel Arrays Sort in Java Bifunction in java 8 Java 8 filters list Java 8 Consumer Interface in Java

Java 9 Features

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

Java 12

What’s new in Java 12

Java 13

Java 13 New Features

Java 14

New Features of Java 14

Java 15

What’s New in Java 15

Java 16

Java 16

Java 17

What is new in Java 17

Java Servlet Tutorial

Java Servlets Tutorial

Java JSP Tutorial

Java JSP Tutorial

Hiberate Tutorial

Hibernate Tutorial

Spring Tutorial

Spring Tutorial

Spring MVC Tutorial

Spring MVC Tutorial

Jenkins Tutorial

Jenkins Tutorial Jenkins java net socket connection time out

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.fma() 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

List all files in a Directory in Java Nonagonal number in Java Null Pointer Exception in Java Package naming convention in Java Packages Program in java Pangram Program in Java PriorityBlockingQueue Class in Java Race Condition in Java Repdigit Numbers in Java Reserved Keywords in Java Rotate matrix by 90 degrees in Java Segment Tree in Java Sierpinski Number in Java Sort Dates in Java Thread Safety and How to Achieve it in Java Normal and Trace of a Matrix in Java Transient variable in Java Tribonacci series in Java Web Crawler in Java Zigzag Traversal of Binary Tree in Java Java Full Stack Java IO filenotfoundexception Java Output Formatting Java Plot Java Pop Java program to print matrix in Z form Java Set to List Java Switch string Java Thread Lifecycle: States and Stages Java Viva Questions and Answers Lazy Propagation in Segment Tree in Java Level order Traversal of a Binary Tree in Java Method chaining in Java Narcissistic Number in Java Java Case Keyword Java Try-Catch Block Java Class KeywordJava concurrency interview questions Java Continue Keyword Java CountDownLatch Java Default Keyword Java Double Keyword Java Editors Java Else Keyword Java Enum Keyword Java Extends keywordJava Finally Keyword Java Font Example of Static import in Java How Many Ways to Create Objects in Java Implementing Queue Using Array in Java Instanceof operator in Java Interchange Diagonal elements in Java Java Arrays Fill Java Char Keyword Convert list to array Java Convert milliseconds to date in Java Copy data/content from one file to another in java CRC Program in Java Creating a Jar file in Java Crown Pattern in Java Difference Between Access Specifiers and Modifiers in Java Difference Between Java and PHP Difference Between replace() and replaceall() in Java Duodecimal in Java Finding middle node of a linked list in Java Group by in Java 8 Hollow Diamond Pattern in Java How annotations work in Java Java Boyer Moore Catalan number in Java Cosmic Superclass in Java Difference between this and super in Java Fall through in Java Figurate Number in Java Java Anon Proxy Java RMI Lazy loading in Java Magnanimous Number in java Shallow copy in Java String to JSON in Java Tetranacci Number in Java Vigesimal in Java Why main method is static in Java Add Time in Java Bellman Ford Algorithm in Java Best Java Libraries Blockchain in Java Blocking Queue in Java Example Bully Algorithm code in Java Contextual keywords in Java Convert JSON File to String in Java Determine the Upper Bound of a Two-Dimensional Array in Java Java.net.ConnectionException Java.net.SocketException Web Service Response Time Calculation in Java 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 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 Convert Char array to string in java Check whether Java is installed or not How to stop execution after a certain time in Java Jagged Array in Java Java ArraylistRemove() Time Complexity Java Swing Time Picker Zigzag Array in Java Array and String based questions in Java Array and String with Examples in Java Best Practices to use String Class in Java What is string in Java why it's immutable Java String Java String Inbuilt functions Java String Matches vs Contains Sum of digits in string in java Check the presence of Substring in a String in java Java import packages Interfaces and Classes in Strings in Java Maximum length of string in java Hidden classes in Java Class memory in Java public static void main string args meaning in java Reverse a String in Java String Concatenation in Java Buffer reader to read string in Java Split String into String Array in Java Reverse a String using Collections in Java Upcasting and Downcasting in Java String Declaration in Java Method Overloading In Java Java Solid Principles Java Architecture Binary Search Java Star Program in Java Java Type Casting Java Pass-by-Reference Java Framework List Java Destructors Java Control Statements Java Byte Code Java Beans Java Identifiers Character Array in Java Java Applications Java Substring Java Session Non-primitive data types in Java Matrix Multiplication in Java JIT in Java Java Tokens Java Externalization Default Virtual Behaviour in C++ vs Java Why we use static in Java Session Tracking in Java Knapsack problem in Java Java Logo Java exception list Java Iterator Java instance variable Frugal number in Java Fork Join in Java Date time API in java Compile time vs Runtime in java Compare time in java AES 256 Encryption in Java Advanced Java skills What is advance Java? User Defined Exception in Java Upcasting in Java Tree Implementation in Java Special Operators in Java Reentrant Lock in Java Perfect Number in Java Java logger Java LinkedList vs ArrayList File Operation in Java Constructor Overloading in Java Conditional operator in Java Concurrent Linked Deque in Java with Examples Command Class in Java Java Break Keyword Best Java IDE Association in Java Access specifiers in Java AbstractSet Class in Java Adapter class in Java Composition in Java Mutable and Immutable in Java Static() Function in Java Traverse through HashMap in Java Vectors in Java Creation of Multi Thread in java Java Enumeration Compile-time Error in Java Java Get Time in UTC Java.sql.Time Format Structure of Java Program Thread Concept in Java Creation of Multi-Thread in Java Enterprise Java Beans POJO in Java Volatile keyword in Java Java Constant Collection Interfaces in Java with Examples Deadlock Prevention and avoidance in Java Java Boolean Keyword Java Byte Keyword Java List Implementations Java Xml Parser Method Overriding in Java RMI program in Java Virtual Function in Java What is interpreter in Java? Advanced Java Viva Questions Application of Array in Java Economical number in Java Iterate JSON array in Java Java callable example Java Command not found Java Date add Days Java File Extension Java Location Java Trim User Defined Custom Exceptions in Java Java array list remove time complexity Java.lang.Exception.NoRunnableMethods Java Map Example Java Obfuscator Java Pi Java Queue Java time local date Java Xmx Uses of Java Applet Life Cycle in Java Best Java Security Framework BigDecimal toString() in Java Jdoodle Java Literals in Java MVC in Java Powerful Number in Java Read the XLSX file in Java Relatively Prime in Java Root exception in java What is anagram in Java? Accessors and Mutator in Java Bottom view of a binary tree in Java Convert List to String in Java Equidigital in Java How to check data type in Java IdentityHashMap in Java Java Clone Array Java LDAP Authentication Java List Node Java Password Generator Magic Square in Java Pancake Sorting in Java Practical Number in Java Sublime Number in Java Sudoku in Java Compare Two Times in Java Diffie Hellman Algorithm in Java How to Reduce Time Complexity in Java Java calculate age Map of Map in Java Minimum XOR value pair in Java Palindrome Partitioning problem in Java Pernicious Number in Java Prime Points in Java Rectangular Numbers in Java Sleep Time in Java The final Keyword in Java Types of Statements in Java Unicode System in Java Zig Zag star and Number Pattern in Java Balanced Prime Number in Java ConcurrentSkipListSet in Java Construct the Largest Number from the Given Array in Java CopyOnWriteArrayList in Java Cyclic Barrier in Java Dangling Else problem in Java Display Unique Rows in a Binary Matrix in Java Empty Statement in Java Factorial of a Large Number in Java Facts about null in Java Rehashing in Java Singleton Design Pattern in Java Zebra Puzzle Problem in Java XOR of Array Elements Except Itself in Java Types of Sockets in Java Thread Synchronization in Java Set Up the Environment in Java Method and Block Synchronization in Java Fibodiv Number in Java House Numbers in Java GCD of Different SubSequences in Java Hogben Numbers in Java Decagonal Numbers in Java Converting Roman to Integer Numerals in java Check if the given array is mirror inverse in Java Caesar Cipher Program in Java Block Swap Algorithm for array rotation in Java Java Binary Tree Binary Strings Without Consecutive Ones in Java Beautiful Array in Java Balanced Parentheses in Java Arithmetic exception in Java Add numbers represented by Linked Lists in Java Two Decimal Places Java Intersection Point of two linked list in Java Find next greater number with same set of digits in Java Getter and Setter Method in Java Example Java Binary to Hexadecimal Java Calculate Average of List Iccanobif Numbers in Java Java delete directory Java For Keyword Java Float Keyword Java Instanceof Keyword Java If Keyword Java Int Keyword Java Import Keyword Java Package Keyword Java Static Keyword Java Public Keyword Java Implements Keyword Java Private keyword Java Protected Keyword Java Short Keyword Java Long Keyword Java Interface Keyword Java Try Keyword Java New Keyword Java Return Keyword Tug of War in Java Types of Events in Java

Types of Sockets in Java

The fundamental idea behind Java's networking capability is the socket. Early in the 1980s, the Berkeley UNIX 4.2BSD version included the socket paradigm. Berkeley socket is the term employed as a result. The socket is the foundation of a contemporary network since it enables a single computer several clients at once and provide various types of data. And to do that, a port - an identified socket on a particular machine - is used. It is stated that the server process "listens" to a port. up until the client establishes a connection with the server. Multiple clients may connect to the same port on the server, but only one client may be active at a time. A multi-threaded server process is necessary to manage several client connections.

Protocol is used to establish socket connections. A low-level routing protocol called Internet Protocol (IP) divides data into individual packets and sends them over the network to a specific address. However, there is no assurance that the packets will arrive at their destination as a result of this. Another higher-level protocol called Transmission Control Protocol (TCP) is able to link together these packets robustly and sort and retransmit them as necessary for a reliable data transmission. User Datagram Protocol (UDP), a third protocol, can be immediately applied to provide quick, unreliable, offline packet transfers.

The higher-level protocol that follows connection establishment depends on the port you are using. The first 1,024 ports are reserved for TCP/IP for some protocols. And many of these may sound extremely familiar to you if you've been using the Internet for a while. Telnet uses port number 23, FTP uses port 21, whose uses port 43, email uses port 25, HTTP uses port 80, finger uses port 79, netnews uses port 119, and so on. Each protocol specifies the manner in which the client should communicate with the port.

Types of Sockets in Java

The following three socket types are supported by Java:

  1. Stream Sockets
  2. Datagram Sockets
  3. Raw Sockets

Stream Sockets

Using TCP, processes can communicate thanks to Stream Sockets. A dependable, two-way, unrepeated, sequential stream of data without record boundaries is offered by stream sockets. The socket is connection-oriented. These sockets allow for the reading and writing of data as streams of bytes once a connection has been made. SOCK STREAM is the socket type.

When a secure connection is required for two network programmes sending and receiving numerous messages, stream sockets are employed. TCP is used by stream sockets to guarantee error-free delivery of messages to their destinations. In reality, IP packets are frequently misdirected or lost in the network. In either case, the IP packet is resent by the receiving TCP after connecting to the issuing TCP. Each stream socket has two are now connected securely as a result of this.

  The client/server applications require the use of stream sockets. The client programme tries to build a stream socket object containing the host IP address of a server programme, the server program's port number (i.e., a network-aware application that needs access to a service) (that is, a network-aware programme that provides a service to client programs). The network management software on the client host receives the IP address and port number from the stream socket initialization code in the client programme.

This software uses IP to provide the server host's IP address and port number via NIC. In an effort to confirm that the server programme is accepting the stream socket's connection requests on the designated port, network management software at the server host tries to retrieve data (via IP) from the NIC. If the server programme is listening, the network management software on the host server will react to the network management software on the client host with a positive acknowledgement.

The server program's stream socket receives the client program's stream socket initialization code, establishes a port number for the client programme, passes the port number to the stream socket of the server application, which utilises that number to distinguish the client.

The stream socket initialization code for the client application responds by throwing an exception object and failing to open a channel of communication (It does not produce an object for a stream socket.)

TCP/IP Client Sockets

To build dependable streaming connections that are two-way, persistent, and point-to-point between hosts on the Internet, TCP/IP sockets are employed. Sockets can be used by the Java I/O system to connect to other programmes running locally or on remote systems connected to the Internet. It's crucial to remember that the applet creates a unidirectional socket connection with the host on which it is loaded. Because it is risky for applets loaded access arbitrary systems via a firewall, this restriction is in place. In Java, there are two different TCP socket types.

One is for the client, the other is for the server. When a client connects, the ServerSocket class acts as a "listener" and does nothing else. ServerSocket is therefore for servers. For clients, there is the Socket class. It's intended to establish a connection with launch from a server socket a protocol exchange. This is due to the fact that Java applications most frequently employ client sockets. connecting the client and server is automatically established when a Socket object is created. No function Object() { [native code] } or method explicitly exposes information about how to set up this connection.

The two constructors that are used to build a client socket are as follows:

  1. IOException is thrown by Socket(InetAddress, ipAddress, int port): Uses a port and an existing InetAddress object to create a socket.
  2. UnknownHostException, IOException are thrown by the function socket(String hostName, int port),: which creates a socket connected to the supplied host and port.

Different instance methods are defined by socket. A socket can always use the techniques listed below to lookup associated address and port information.

  1. int getPort(): It gives back the remote port that the invoked Socket object is attached to. In the absence of a connected socket, it returns 0.
  2. int getLocalPort(): the local port that the calling Socket object is linked to is returned. If the socket is unbound, it gives back -1.
  3. InetAddress getInetAddress(): It gives back the InetAddress connected to the Socket object. In the absence of a connected socket, it returns null.
  4. InputStream getInputStream() throws IOException: Gets the InputStream connected to the socket that is invoking the command.
  5. OutputStream getOutputStream( ) throws IOException: gives back the OutputStream connected to the calling socket.
  6. connect( ): allows for the specification of a new connection
  7. isConnected( ): If a server connection is present, the function returns true.
  8. isBound( ): if the socket is connected to an address, it returns true.
  9. isClosed( ): If the socket is shut, the function returns true.

A straightforward socket example is provided by the programme below. opens a connection to the InterNIC server's "whois" port (port 43), gives a command-line input to the socket, then publishes the results. The InterNIC will attempt to locate the dispute using the Internet domain name that is registered before returning the IP address and contact details for that website.

import java.net.*;  
import java.io.*;  
public class WhoisClient {  
    public static void main(String[] args) {  
        if (args.length < 1)   
        return;  
        String domainName = args[0];  
        String hostname = "whois.internic.net";  
        int port = 43;   
        try (Socket socket = new Socket(hostname, port)) {  
            OutputStream output = socket.getOutputStream();  
            PrintWriter writer = new PrintWriter(output, true);              
            writer.println(domainName);  
            InputStream input = socket.getInputStream();  
            BufferedReader reader = new BufferedReader(new InputStreamReader(input));  
            String line;  
            while ((line = reader.readLine()) != null) {  
                System.out.println(line);  
            }  
        }   
        catch (UnknownHostException ex) 
{  
             System.out.println("Server not found: " + ex.getMessage());  
         }   
        catch (IOException ex) {  
             System.out.println("I/O error: " + ex.getMessage());  
        }  
    }  
}  
Expected Output: 
WhoisClient

The programme operates as follows. To begin, the socket is built with the host name "internic.net" and port number 43, which is a website that responds to port 43 whois requests. Additionally, the socket opens up for both streams, both input and output.The string that comprises the name of the website from which we wish to obtain information is then created. The outcome is displayed once through socket input, the response is read.

Datagram Sockets

Datagram sockets let processes communicate using UDP. Bidirectional message flow is supported using datagram sockets. It is a socket without a connection. It is possible for a datagram socket process to receive duplicate messages as well as messages in a different order from the one in which they were transmitted. The data's record boundaries are still present. SOCK DGRAM is the socket type.

The majority of networking requirements can be met by TCP/IP-style networking. It offers a stream of packet data that is serialised, predictable, and trustworthy. But there is a price to this. TCP uses numerous cutting-edge algorithms to handle congestion control on congested networks and to prepare for the worst-case scenario of packet loss. This results in a fairly ineffective method of data transportation. Datagrams offer a different option.

Large volumes of information are sent between machines called datagrams. There is no assurance that the datagram will arrive or perhaps that someone will be there to grab it once it has been released for its intended use. Similar to this, there is no assurance that the datagram was not harmed in transit or that the sender is still present to receive a response when it is received.

Java uses two classes to construct Adding datagrams to the UDP protocol: the DatagramPacket object serves as the data container and the DatagramSocket provides the means of sending or receiving datagram packets.

Four public constructors are defined by DatagramSocket. Here are a few of them:

  • Creates a Datagram socket linked to any open port on the local machine, however DatagramSocket() produces SocketException instead.
  • (int Port) DatagramSocket throws A DatagramSocket is created with the SocketException exception and is bound to the port given by the port.
  • DatagramSocket(int port, InetAddress ipAddress), which constructs a DatagramSocket bound to the supplied port and InetAddress, throws a SocketException.
  • Constructs a DatagramSocket bound to the supplied SocketAddress. DatagramSocket(SocketAddress address) throws SocketException. The concrete class InetSocketAddress implements the abstract class SocketAddress. In InetSocketAddress, an IP address and port number are combined. If a problem arises during the socket creation process, any user may throw a SocketException.

Many methods are defined by DatagramSocket. Here, the functions send() and receive()—two of the most crucial—are displayed:

  • IOException is thrown by the void send() method, which sends the packet to the port indicated by the DatagramPacket packet.
  • The function void receive(DatagramPacket packet) throws an IOException and waits for a packet to be received from the port that the packet specifies before returning the outcome.

You can access additional methods that provide you access to different DatagramSocket characteristics.

Here are several examples:

  • InetAddress getInetAddress(): The address is returned if the socket is established. If not, null is returned.
  • int getLocalPort() of type returns the local port's number.
  • Gets the port number that the socket is connected to using the int getPort() method. If the socket is not connected to a port, it returns -1.
  • The function isBound(), which returns true if the socket is bound to an address, checks this. Otherwise, it returns false.
  • If the socket is linked to a server, the boolean isConnected() function will return true. Alternatively, it returns false.
  • sets void It throws SoTimeout(int millis). The time-out period is set to the amount of milliseconds that have elapsed in millis due to the SocketException.

Datagram Packet

Multiple constructors are defined by DatagramPacket. Here are four of them:

  • DatagramPacket(byte data[], int size]) specifies the size of a packet as well as a buffer that will accept the data. It is employed for DatagramSocket data reception.
  • We can define an offset within the buffer at which data will be put using DatagramPacket(byte data[], int offset, and int size).
  • It specifies a destination address and port that a DatagramSocket will use to decide where the data in the packet will be transmitted. DatagramPacket(byte data[], int size, InetAddress ipAddress, int port)
  • Transmits packets starting at the provided offset into the data using the following syntax: DatagramPacket(byte data[], int offset, int size, InetAddress ipAddress, int port).

Raw Sockets

Access to ICMP (Internet Control Message Protocol) is made possible using raw sockets. The exact nature of these sockets, which are often datagram-oriented, depends on the protocol's given interface. Most applications do not suit raw sockets. It is offered to aid in the creation to gain more information about new communication protocols intricate parts of protocols already in use. Raw sockets can only be used by root processes. The type of socket is SOCK RAW.

The address is the primary component of the Internet. On the Internet, each computing gadget has a personal one. Each Internet-connected computer has a specific identification number called an Internet address. At first, every Internet address was a 32-bit value, or four 8-bit values. This kind of address is defined by IPv4 (Internet Protocol, version 4). However, IPv6 (Internet Protocol, version 6) is a new address scheme that has already been implemented.



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