Java Tutorial

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Java Loops

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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 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 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 Java Read JSON 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 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 Statements in java Prepared statement in Java Resultset in java Java ResultSetMetaData DatabaseMetaData in Java Callable Statement in Java Transaction Management in java

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 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 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 find the length of an Array 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 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 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 Split String by Comma in Java How to remove special characters from String in Java How to remove last character from String 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 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 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 Difference between String and Char Array in Java Buffer reader to read string in Java

Java Read File to String

There are different ways to deal with forming and examining a text record. This is normal while dealing with various applications.

There are different ways to deal with looking at a plain text record in Java for example you can utilize FileReader, BufferedReader or Scanner to examine a text report.

Given a message record, the undertaking is to peruse the items in a document present in a nearby registry and putting away it in a string.

Consider a record present on the framework to be specific say it be 'file.txt'.

Give the arbitrary substance access the record be as embedded underneath in the pretag block.

Presently we will talk about out different ways of accomplishing something similar. The substance inside document 'file.txt' is as displayed in the outline block.

Methods:

There are multiple ways of accomplishing the objective and with the progression of the form in java, explicit strategies are there spread out which are talked about successively.

  • Using File.readString() strategy
  • Using readLine() strategy for BufferReader class
  • Using File.readAllBytes() strategy
  • Using File.lines() strategy
  • Using Scanner class

Using File.readString() strategy: The readString() technique for File Class in Java is utilized to peruse items to the predefined document.

Syntax:

Files.readString(filePath);

Boundaries: File way with information type as Path

Return Value: This technique returns the substance of the document in String design.

Note: File.readString() technique was presented in Java 11 and this strategy is utilized to peruse a document's substance into String.

//example to understand more about this

// Java Program Illustrating Reading a File to a String

// Utilizing File.readString() strategy

// Bringing in required classes

import java.io.*;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
// Principal class
public class RS1 {
// Principal driver strategy
	public static void main(String[] args) throws IOException
	{


		// Making a way picking document from nearby
		// catalog by making an object of Path class
		Way filename = Path.of("C:\\Users\\VICTUS\\Desktop\\bhoomika.txt");
		// Presently calling Files.readString() strategy to
		// peruse the record
		String str = Files.readString(fileName);
		// Printing the string
		System.out.println(str);
	}
}

Using readLine() strategy for BufferReader class:

BufferedReader is an item used to peruse text from a person input stream. The readLine() strategy present in BufferReader technique is utilized to peruse the record each line in turn and return the substance.

Linguistic structure: public String readLine() throws IOException

Boundaries: This strategy acknowledges no boundary.

Return Value: This strategy returns the string that is perused by this technique and prohibits any end image accessible. Assuming the cradled stream has finished and there is no line to be perused then this technique brings NULL back.

Special cases: This technique tosses IOException if an I/O mistake happens.

//simple program
// Java Program Illustrating Reading a File to a String
// Using readLine() method of BufferReader class
// Importing required classes
import java.io.*;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
// Main class
public class RS2 {
	// To read file content into the string
	// using BufferedReader and FileReader
	private static String method(String filePath)
	{
		// Declaring object of StringBuilder class
		StringBuilder builder = new StringBuilder();
		// try block to check for exceptions where
		// object of BufferedReader class us created
		// to read filepath
		try (BufferedReaderbuffer = new BufferedReader(new   											FileReader(filePath))) {


			String str;
			// Condition check via buffer.readLine() method
			// holding true upto that the while loop runs
			while ((str = buffer.readLine()) != null) {
							builder.append(str).append("\n");
			}
		}


		// Catch block to handle the exceptions
		catch (IOException e) {


			// Print the line number here exception occurred
			// using printStackTrace() method
			e.printStackTrace();
		}


		// Returning a string
		return builder.toString();
	}
}

Using File.readAllBytes() strategy: File.readAllBytes() technique is utilized to peruse every one of the bytes from a document.

The system guarantees that the record is shut when all bytes have been analyzed or an I/O mess up, or other runtime exemption, is tossed.

 Resulting to scrutinizing all bytes, we pass those bytes to the string class constructor to make a string.

Language structure:

public static byte[] ReadAllBytes (string way);

Boundary: Path which is the predetermined document to open for perusing.

Approach:

Proclaiming a vacant string

get() strategy for Path class helps in bringing the record by passing as a contention to it.

Presently readAllBytes() strategy for the File class is utilized to add the above record by passing to it.

Ultimately, print the string.

Exceptions:

  1. ArgumentException: The way is a zero-length string, contains just void area, or at least one invalid characters as characterized by InvalidPathChars.
  2. ArgumentNullException: The way is invalid.
  3. PathTooLongException: The predefined way, record name, or both surpass the framework characterized greatest length.
  4. DirectoryNotFoundException: The predetermined way is invalid.
  5. IOException: An I/O mistake happened while opening the record.
  6. UnauthorizedAccessException: This activity isn't upheld on the ongoing stage.Then again the way shown a list. Then again the visitor doesn't have the normal assent.
  7. FileNotFoundException: The record determined in the way was not found.
  8. NotSupportedException: The way is in an invalid organization.
  9. SecurityException: The guest doesn't have the necessary authorization
//simple program


// Java Program Illustrating Reading a File to a String
// Utilizing File.readAllBytes() strategy


// Bringing in required classes
import java.io.*;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;


// Primary class
public class RS3 {


	// Strategy 1
	// To peruse the document content into string with
	// Files.readAllBytes(Path way)
	confidential static String method(String file_path)
	{
		// Proclaiming an unfilled string
		String str = "";
		// Attempt block to check for special cases
		try{
			// Perusing all bytes structure record and
			// putting away that in the string
			str = new String(
				Files.readAllBytes(Paths.get(file_path)));
		}


		// Get block to deal with the exemptions
		get (IOException e) {


			// Print the special case alongside line number
			// utilizing printStackTrace() technique
			e.printStackTrace();
		}


		return str;
	}


	// Strategy 2
	// Principal driver strategy
	public static void main(String[] args)
	{


		// Way is passed from nearby catalog of machine
		// what's more, put away in a string
		String filePath = "C:\\Users\\VICTUS\\Desktop\\file.txt";
		// Presently call Method1 to
		// peruse the substance in above registry
		System.out.println(method(filePath));
	}
}

Using File.lines() strategy: File.lines() strategy is utilized to peruse all lines from a document to stream. Then, at that point, the bytes from the record are decoded into characters utilizing the predetermined charset like UTF_8.

Language structure:

public static Stream<String> lines(Path way, Charset cs) throws IOException

Boundaries: It conventionally takes two boundaries:

Charset to use for unraveling.

Way of the record.

Return Type: The lines from the record as a string.

//simple program


// Java Program Illustrating Reading a File to a String
// Utilizing File.lines() strategy


// Bringing in required classes
import java.io.*;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.stream.Stream;


// Primary class
public class RS4 {


    // Strategy 1
    // To peruse the document content into the string with -
    // Files.lines()
    confidential static String method(String filePath)
    {


        // Pronouncing an object of StringBuilder class
        StringBuilder contentBuilder = new StringBuilder();


        // attempt block to check for special cases


        // Perusing document to string utilizing File.lines() technique
        // also, putting away it in an object of Stream class
        attempt (Stream<String> stream
             = Files.lines(Paths.get(filePath),
                           StandardCharsets.UTF_8)) {
            stream.forEach(
                s - > contentBuilder.append(s).append("\n"));
        }


        // Get block to deal with the special cases
        get (IOException e) {


            // Print the line number where exemption happened
            // utilizing printStackTrace() strategy
            e.printStackTrace();
        }


        // Returning the string manufacturer by
        // calling tostring() strategy
        return contentBuilder.toString();
    }

    // Strategy 2

    // Principal driver technique
    public static void main(String[] args)
    {


        // Custom record way is put away as string
        String filePath = "C:\\Users\\HP\\VICTUS\\bhoomika.txt";


        // Calling strategy 1 to peruse content of a record
        System.out.println(method(filePath));
    }
}

Using Scanner class: Scanner class works by breaking the contribution to tokens that are consecutively recovered from the information stream.

 Scanner class has two in form strategies named straightaway() and hasNext(). Both of these in-form strategies return objects of type String.

//simple program
// Java Program Illustrating Reading a File to a String
// Utilizing straightaway() and hasNext() strategy for Scanner class


// Bringing in required classes
import java.io.*;
import java.io.IOException;
import java.nio.file.Path;
import java.util.Scanner;


// Principal class
public class RS5 {


    // Principal driver strategy
    public static void main(String[] args)
     throws IOException
    {


        // Making object of Path class where custom neighborhood
        // catalog way is passed as contentions utilizing .of()
        // strategy
        Way fileName
            = Path.of("C:\\Users\\VICTUS\\Desktop\\bhoomika.txt");


        // Making an object of Scanner class
        Scanner sc = new Scanner(fileName);


        // It turns out as expected till there is single component left
        // by means of hasNext() strategy
        while (sc.hasNext()) {
            // Repeating over components in object
            System.out.println(sc.next());
        }


        // Shutting scanner class object to keep away from mistakes and
        //  let loose memory space
        sc.close();
    }
}



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