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 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 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 Open File

Java Desktop class give an open() strategy to open a filr. It has a place with a java.awt package. Work area execution is stage subordinate, so it is important to check the working framework upholds Desktop or not.

The Desktop class searches for a related application enrolled on the local work area to deal with a file.

How to open a file in java?

There are following ways of opening a file in Java:

  • Java Desktop class
  • Java FileInputStream class
  • Java BufferedReader class
  • Java FileReader class
  • Java Scanner class
  • Java nio bundle

Java desktop class: Java Desktop class give an open() technique to open a record. It has a place with a java.awt bundle.

Work area execution is stage subordinate, so it is important to check the working framework upholds Desktop or not.

The Desktop class searches for a related application enrolled on the local work area to deal with a record.

In the event that there is no related application or application is neglects to be sent off, it tosses the FileNotFoundException.

  • Dispatches the client default program to show a predefined URI.
  • Dispatches the client default mail client with a discretionary mail-to URI.
  • Dispatches the enrolled application to open, alter, or print a predefined record.
  • The open() strategy for Desktop class dispatches the related application to open a record. It takes a record as a contention.

The mark of the technique is:  public void open (File record) tosses IOException

The technique tosses the accompanying special cases:

  1. NullPointerException: If the record is invalid.
  2. IllegalArgumentException: It is tossed when the record doesn't exist.
  3. IOException: It is tossed when there is no application related with the given record type.
  4. UnsupportedOperationExecution:  If the ongoing stage doesn't uphold the Desktop.Action.Open activity.
//open file example no 1
import java.awt.Desktop;
import java.io.*;
public class FileOpen1
{
public static void main(String[] args)
{
try
{
//constructor of document class having record as contention
File record = new File("C:\\demo1\\demo1file.txt"); //here record is even termed as file
if(!Desktop.isDesktopSupported())//check in the event that Desktop is upheld by Platform or not
{
System.out.println("not upheld");
return;
}
Work area work area = Desktop.getDesktop();
if(file.exists())//checks document exists or not
desktop.open(file);//opens the predetermined document
}
catch(Exception e)
{
e.printStackTrace();
}
}
}

At the point when we run the above program, it opens the predetermined text record in the default content manager. We can likewise open the .docx, .pdf, and .jpg record.

Java FileInputStream class: Java FileInputStream class is utilized to open and peruse a record. We can open and peruse a record by utilizing the constructor of the FileInputStream class.

The mark of the constructor is:

public FileInputStream(File record) throws FileNotFoundException

It acknowledges a record as a contention. It tosses FileNotFoundException on the off chance that the record doesn't exist or document name is a registry.

//open file example 2

import java.io.*;
import java.util.Scanner;
public class FileOpen
{
public static void main(String args[])
{
try
{
//constructor of document class having record as contention
Document file=new File("C:\\demo1\\demo1file.txt");
FileInputStream fis=new FileInputStream(file);//opens an association with a real document
System.out.println("file content: ");
int r=0;
while((r=fis.read())!=-1)
{
System.out.print((char)r);//prints the substance of the document
}
}
catch(Exception e)
{
e.printStackTrace();
}
}
}

Java BufferedReader class: Java BufferedReader class peruses text from a person input stream. It has a place with a java.io bundle. We utilize the constructor of the BufferedReader class to open or peruse a record.

The mark of the constructor is: public BufferedReader(Reader in)

It makes a buffering character-input stream that utilizes a default? sized input cradle. It utilizes a default size input support.

//open file example no 3

import java.io.*;
import java.util.Scanner;
public class FileOpen3
{
public static void main(String args[])
{
try
{
//constructor of File class having document as contention
Document file=new File("C:\\demo1\\demo1file.txt");
//makes a cushion peruser input stream
BufferedReader br=new BufferedReader(new FileReader(file));
System.out.println("file content: ");
int r=0;
while((r=br.read())!=-1)
{
System.out.print((char)r);
}
}
catch(Exception e)
{
e.printStackTrace();
}
}
}

Java FileReader class: Java FileReader class is likewise utilized for opening and perusing a record. It has a place with a java.io bundle. It is a comfort for perusing characters of the documents. It is utilized for perusing crude bytes utilizing the FileInputStream class. We utilize the constructor of the FileInputStream class to open and peruse a record.

The mark of the constructor is:

public FileReader(File record) tosses FileNotFoundException

It acknowledges a record as a contention. It tosses the FileNotFoundException on the off chance that the predefined record doesn't exist or the document name is a registry.

//open file example no 4:

import java.io.*;
public class FileOpen4
{
public static void main(String args[])
{
try
{
//constructor of the File class having document as a contention
FileReader fr=new FileReader("C:\\demo11\\demo1file.txt");
System.out.println("file content: ");
int r=0;
while((r=fr.read())!=-1)
{
System.out.print((char)r);//prints the substance of the document
}
}
catch(Exception e)
{
e.printStackTrace();
}
}
}

Java Scanner Class:  Java Scanner class is likewise utilized for opening and perusing a record. The Scanner class has a place with java.util bundle. The constructor of Scanner class is utilized for opening and perusing a document.

 The mark of the constructor is:

public scanner (File source) tosses FileNotFoundException

It acknowledges a record (to be checked) as a contention. It likewise tosses FileNotFoundException, in the event that the wellspring of the record isn't found.

//open file program example 5

import java.io.File;
import java.util.Scanner;
public class FileOpen5
{
public static void main(String[] args)
{
try
{
Record file=new File("C:\\demo1\\demo1file.txt");
Scanner sc = new Scanner(file);//record to be checked
while (sc.hasNextLine())//returns valid if and provided that scanner has another token
System.out.println(sc.nextLine());
}
catch(Exception e)
{
e.printStackTrace();
}
}
 }

Java nio package:  readAllLines() technique: The readAllLines() strategy is the technique for File class.

It peruses all lines from a record and bytes from the document are decoded into characters utilizing UTF-8 charset. It returns the lines from the document as a rundown.

The mark of the strategy is:

public static List<String> readAllLines(Path way) throws IOException

Where way is the record way.

Above technique is identical to summoning the accompanying:

File.readAllLines(path, Standard CharSets.UTF_8)

Collections.emptyList(): The emptyList() technique is the strategy for Collection class which have a place with java.util bundle. Getting an unfilled list is utilized.

 The mark of the technique is:  public static last <T> List <T> emptyList()

//open file example no 6

import java.util.*;
import java.nio.charset.StandardCharsets;
import java.nio.file.*;
import java.io.*;
public class FileOpen6
{
public static List<String> readFileInList(String fileName)
{
List<String> lines = Collections.emptyList();
try
{
lines=Files.readAllLines(Paths.get(fileName), StandardCharsets.UTF_8);
}
get (IOException e)
{
e.printStackTrace();
}
bring lines back;
}
public static void main(String[] args)
{
List l = readFileInList("C:\\demo1\\demo1file.txt");
Iterator<String> itr = l.iterator();//access the components
while (itr.hasNext())//returns valid if and provided that scanner has another token
System.out.println(itr.next());//prints the substance of the record
}
}



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