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

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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 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


Java Serialization Java transient


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


Java AWT


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 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

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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


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 Convert Char array to string in java Check whether Java is installed or not How to calculate time difference in Java 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




It is a standard set of rules that allow electronic devices to communicate with each other.

The http protocol

The http protocol is for data communication, distributing, collaborating, hypermedia information systems, on the World Wide Web. The http is a TCP/IP based communication protocol that is used to deliver data on the World Wide Web.

The http protocol is the client server-based architecture where web browsers, robots and search engines, etc., acts like http clients, and the server acts as a server.

The http client requests a URL, which is having a protocol version, a domain name followed by the file or directories name. The http server responds, including the message’s protocol version and a success or error code, followed by a MIME-like message containing server information, entity meta-information, and possible entity-body content.


It is a http specific URLConnection. It works for http protocol only. You can get information about any http URL such as header information, status code, response code by using the HttpURLConnection class.


  • It is an abstract class directly extending from the URLConnection class.
  • It is a http specific URLConnection, works for http protocol only. It extends all the functionality of its parent class with additional http related features.

Getting object of HttpURLConnection class:

 1. public URLConnection openConnection()throws IOException()
 //returns the object of URLConnection class.
 2.  By typecasting it to HttpURLConnection type as given we get object of the HttpURLConnection.
 URL url=new URL("http://www.javatpoint/java-tutorial");
 HttpURLConnection hcon=(HttpURLConnection)url.openConnection(); 


  1. Creating the URL object by using the

URL url=new URL(“http://www.javatpoint/java-tutorial”);

  • Obtain a URLConnection object by calling openConnection() of the URL class and casting the result to HttpURLConnection.

HttpURLConnection hcon=(HttpURLConnection)url.openConnection();

Methods in HttpURLConnection class:

Method Description
public boolean getInstanceFollowRedirects() It returns true or false depending on the automatic instance redirection set or not.
public InputStream getErrorStream() It gets the error stream if the server cannot be connected or some error occurred. It can contain information about how to fix the error.
public Permission getPermission()  It returns permission required to connect to the server.
public void setChunkedStreamingMode(int n)throws IllegalStateException This mode is used when the content length is not known. Instead of creating a buffer of fixed length and writing it to the server, content is broken into chunks and then written. Not all servers support this mode.
public boolean usingProxy() It returns true if the connection is established using a proxy, else false.  
public void disconnect ()  It indicates that other requests to the server are disconnected.
public static boolean getFollowRedirects() It returns true or false depending upon if there is an automatic redirection or not.
public void setFollowRedirects(boolean b) It sets whether a 3xx response code requests redirect automatically or not.
public void setFixedLengthStreamingMode(long n/int n)throws IllegalStateException It used to set the length of a content written on the output stream if it knows in advance.
public String getHeaderField() It returns the n header field, or null if it does not exist. It overrides the getHeaderField method of URLConnection class.
public String getResponseMessage() It retrieves the response message.
protected String getRequestMethod() It returns the request method.
protected void setRequestMethod(String method)throws ProtocolException It is used to set the request method. The default is GET.
protected int getResponseCode() To retrieve the response status from the server.

Example 1: To read the header information

public class httpcon1
public static void main(String s[])
URL url=new URL("");
HttpURLConnection h1=(HttpURLConnection)url.openConnection();
for(int i=1;i<=8;i++)
}catch(Exception e){

The output of the above program:

read the header information

Example 2: To use http accessing webpage.

To access http client resources via the HTTP protocol. The URL class provides the address to a web resource. HttpURLConnection allows to create an InputStream. By using the InputStream, you can use it to read the file.

public class httpcon1{
private static final String line = System.getProperty("line.separator");
public static void main(String s1[]) { 
try {
URL url = new URL("");
HttpURLConnection con = (HttpURLConnection) url.openConnection();
String readStream = readStream(con.getInputStream());           
} catch (Exception e) {
private static String readStream(InputStream in) {
StringBuilder sb = new StringBuilder();
try (BufferedReader reader = new BufferedReader(new InputStreamReader(in));) {
 String nextLine = "";
 while ((nextLine = reader.readLine()) != null) {
 sb.append(nextLine +line); 
 } catch (IOException e) {
        return sb.toString();

Explanation of the above program:

  • The URL class is used to create the URL object.
  • The openConnection() of the URL is to create an object of the URLConnection, which is typecasted to HttpURLConnection.
  • The StringBuilder in Java represents a mutable sequence of characters. The StringBuilder class differs from the StringBuffer class based on synchronization. It is recommended to use this class in comparison with StringBuilder as it will be faster under most implementations. An instance of StringBuilder is not safe for use by multiple threads.
  • An InputStreamReader changes byte streams to character streams. It reads bytes and converts them into characters. A BufferedReader is a class in Java that reads text from a character-input stream, buffering characters for the reading of lines and arrays. The readLine() method of the BufferedReader class reads a line of text.

The output of the above program:

Explanation of the above program

Example 3: To get the return code from a webpage.

Returns code is a standardized code that is returned by the webserver if some specific situation has occurred.

The commonly used return codes are:

Return code Explanation
200 ok
301 Permanent redirect to another webpage
400 Bad request
404 Not found
public class httpcon1 {
public static void main(String s1[]) throws IOException {
String urltext = "";
URL url = new URL(urltext);
int responseCode = ((HttpURLConnection) url.openConnection()).getResponseCode();

The output of the above:

To get the return code from a webpage.

Example 4: To describe the kind of web resource.

The internet media type(MIME), describes the kind of web resource.

public class httpcon1 {
public static void main(String s1[]) throws IOException {
String urltext = "";
URL url = new URL(urltext);
String contentType = ((HttpURLConnection) url.openConnection()).getContentType();

The output of the program:

describe the kind of web resource