Atomic File Write (move with ATOMIC_MOVE)

import java.io.IOException;
import java.nio.file.*;
import static java.nio.file.StandardCopyOption.*;

class Demo {
    static void atomicWrite(Path target, byte[] data) throws IOException {
        Path tmp = Files.createTempFile(target.getParent(),
            "." + target.getFileName() + ".", ".tmp");
        try {
            Files.write(tmp, data);
            Files.move(tmp, target,
                ATOMIC_MOVE, REPLACE_EXISTING);
        } catch (IOException e) {
            Files.deleteIfExists(tmp);
            throw e;
        }
    }

    public static void main(String[] args) throws IOException {
        atomicWrite(Path.of("/var/lib/myapp/state.json"),
            "{\"ready\":true}\n".getBytes());
    }
}