Write a UTF-8 file.

Write a Java string to a file using an explicit text encoding.

import java.util.*;
import java.nio.file.*;
import java.nio.charset.StandardCharsets;

public class Main {
    public static void main(String[] args) throws Exception {
        Files.writeString(Path.of("notes.txt"), "hello\n", StandardCharsets.UTF_8);
        System.out.println("Saved notes.txt");
    }
}

Expected output EXAMPLE

Saved notes.txt

Details

Save as Main.java. Compile with javac Main.java, then run java Main. Uses only the Java standard library; tested with OpenJDK 21.

Keep in mind

Replaces notes.txt if it exists.

✓ Verified

Tested on Ubuntu 24.04.5 LTS · 2026-11-02 17:59:42 UTC · openjdk 21.0.12.1 2026-08-18 · openjdk-21-jdk-headless 21.0.12.1+1-1~24.04.4

Test inputs, results and environment

The exact published code ran in a dedicated Linux test container with prepared inputs. Unprivileged snippet process, external networking disabled, read-only root filesystem, and a fresh temporary working directory. Fixtures and output records are isolated from the application database. Testing covers this example and its stated checks, not every input, operating system, or runtime version. The Linux container shares its host's kernel; this is not a native Windows test.

Architecture / host kernel: x86_64 / 6.18.54.1-microsoft-standard-WSL2
Snippet identity / locale: uid=65534, gid=65534 (unprivileged) / C.UTF-8
Interpreter invocation: javac Main.java && java Main
Container image ID: sha256:32dc2d998158b6554c99b73b533f423696a0f3e31e8cbea9db10b5eee9a2fadd
Code SHA-256: d2ca7f041effc224a8fabb0a3d6ec12923c235d100708e91d43ff7da7aa53634
Dependencies: openjdk-21-jdk-headless 21.0.12.1+1-1~24.04.4

Test input setup

These are the prepared inputs used by the test harness. See Details above for the prerequisites and how to run this example.

# No input files required.

Observed standard output

Saved notes.txt

Exit code: 0. Standard error: empty. Validation: Exact stdout comparison. System-dependent values above are one recorded run.

Additional assertions that passed

Checks recorded by the test harness. Where Python assertions are shown, browser cases use Playwright and simulator cases may inspect pin transitions: result.stdout is captured output, work is the temporary directory, and Path is pathlib.Path. The harness also imports json and csv.

assert Path('notes.txt').read_text() == 'hello\n'

# Java # write