Count Number of Lines Present in the File in Java

Exercise:

Write a Java Program to count number of lines present in the file.

1.count using Scanner class

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import java.io.File;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        int count = 0;
        try {
            // create a new file object
            File file = new File("input.txt");

            // create an object of Scanner
            // associated with the file
            Scanner sc = new Scanner(file);

            // read each line and
            // count number of lines
            while(sc.hasNextLine()) {
                sc.nextLine();
                count++;
            }
            System.out.println("Total Number of Lines: " + count);

            // close scanner
            sc.close();
        } catch (Exception e) {
            e.getStackTrace();
        }
    }
}
Click Here to View the Output!
First Line 
Second Line 
Third Line
Click Here to View the Explanation!
  • This program is used to find the number of lines in a file by using an object of the class java.util.Scanner.
  • Initially, an integer variable count is initialized as count = 0 and a try catch block, that will hold the scanner object.
  • A File object file is created that will take the file input.txt as a parameter.
  • Then a Scanner object is created that will take this File object as a parameter.
  • A while loop is then initialized that will use sc.hasNextLine() method of the Scanner class to loop through the lines of the file input.txt until it is true.
  • The sc.nextLine() method will access all the lines in the file and each time an increment of one occurs in the count variable.
  • The loop will end when sc.hasNextLine() becomes false.
  • In the end, the final value of the variable count will be printed depicting the number of lines in input.txt.

2.count using java.nio.file package

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import java.nio.file.*;

public class Main {
    public static void main(String[] args) {

        try {

            // make a connection to the file
            Path file = Paths.get("input.txt");

            // read all lines of the file
            long count = Files.lines(file).count();
            System.out.println("Total Lines: " + count);

        } catch (Exception e) {
            e.getStackTrace();
        }
    }
}
Click Here to View the Output!
This is the article on Java Examples. 
The examples count number of lines in a file. 
Here, we have used the java.nio.file package.
Click Here to View the Explanation!
  • This program is used to find the number of lines in a file by using the package java.nio.file.
  • In the try catch block, a connection is established with the file through the Paths.get() method.
  • A lines() method is used to read all the lines in a file by taking the file object as input. And at the same time, counting the number of these lines using the count() method and storing the output in a long type variable count. The expression is as follows: long count = Files.lines(file).count()
  • Finally, the value in count is printed which will give the total number of lines in the input.txt.