how to count lines from txt java

To count the number of lines in a text file in Java, you can use the BufferedReader class from the Java I/O library.

Here is an example of how you can use the BufferedReader class to count the number of lines in a text file in Java:

try (BufferedReader reader = new BufferedReader(new FileReader("file.txt"))) {
  int lines = 0;
  while (reader.readLine() != null) {
    lines++;
  }
  System.out.println("Number of lines: " + lines);
} catch (IOException e) {
  e.printStackTrace();
}

This code creates a BufferedReader object to read the text file "file.txt". It then uses a while loop to read each line of the file using the readLine method of the BufferedReader object. For each line read, it increments a counter variable called lines. When the readLine method returns null, which indicates the end of the file, the loop is terminated and the value of the lines variable is printed to the console.

The BufferedReader class provides a convenient way to read a text file line by line. It reads the file in chunks and stores the data in a buffer, which allows you to read the file efficiently.

Note that this code uses a try-with-resources statement to ensure that the BufferedReader object is closed properly after the reading is finished. The BufferedReader class implements the AutoCloseable interface, which allows it to be used in a try-with-resources statement.

You will need to import the java.io.BufferedReader, java.io.FileReader, and java.io.IOException classes in your code and make sure that your project has the necessary dependencies to use the Java I/O library.