Java tutorial
import java.io.BufferedWriter; import java.io.IOException; import java.nio.charset.Charset; import java.nio.file.Files; import java.nio.file.Path; import java.nio.file.Paths; import java.nio.file.StandardOpenOption; public class Test { public static void main(String[] args) throws IOException { String newName = "asdf"; Path file = Paths.get("/users.txt"); try (BufferedWriter writer = Files.newBufferedWriter(file, Charset.defaultCharset(), StandardOpenOption.APPEND)) { writer.newLine(); writer.write(newName, 0, newName.length()); } } }