how to read from a txt file in java

/**
 * @author lautturi.com
 * Java example: read a text file in java
 */

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

public class Lautturi {

	public static void main(String[] args) throws IOException {

		try (BufferedReader br = new BufferedReader(new FileReader("test.txt"))) {
			StringBuilder sb = new StringBuilder();
			String line = br.readLine();

			while (line != null) {
				sb.append(line);
				sb.append(System.lineSeparator());
				line = br.readLine();
			}
			String filecontent = sb.toString();
			System.out.println(filecontent);
		}

	}
}

output:

hello
lautturi
java
world