What value does readLine() return when it has reached the end of a file?

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The readLine() method returns null when it has reached the end of a file.

In Java, the readLine() method is typically associated with reading data from a BufferedReader or a similar class that reads characters from a stream. When readLine() reaches the end of a file, it returns null.

Here’s a simple example using BufferedReader:

java
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class ReadFileExample {
public static void main(String[] args) {
String fileName = "example.txt";

try (BufferedReader br = new BufferedReader(new FileReader(fileName))) {
String line;
while ((line = br.readLine()) != null) {
System.out.println(line);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}

In this example, the readLine() method is used in a while loop to read lines from the file until it reaches the end. When the end of the file is reached, readLine() returns null, and the loop terminates.