Java에서 텍스트 파일에 대용량 데이터를 쓸 때 쓰기 속도를 최적화하려면 어떻게 해야 합니까?

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.Writer;
import java.util.ArrayList;
import java.util.List;

public class FileWritingPerfTest {

    private static final int ITERATIONS = 5;
    private static final double MEG = (Math.pow(1024, 2));
    private static final int RECORD_COUNT = 4000000;
    private static final String RECORD = "Help I am trapped in a fortune cookie factory\n";
    private static final int RECSIZE = RECORD.getBytes().length;

    public static void main(String[] args) throws Exception {
        List<String> records = new ArrayList<String>(RECORD_COUNT);
        int size = 0;
        for (int i = 0; i < RECORD_COUNT; i++) {
            records.add(RECORD);
            size += RECSIZE;
        }
        System.out.println(records.size() + " 'records'");
        System.out.println(size / MEG + " MB");

        for (int i = 0; i < ITERATIONS; i++) {
            System.out.println("\nIteration " + i);

            writeRaw(records);
            writeBuffered(records, 8192);
            writeBuffered(records, (int) MEG);
            writeBuffered(records, 4 * (int) MEG);
        }
    }

    private static void writeRaw(List<String> records) throws IOException {
        File file = File.createTempFile("foo", ".txt");
        try {
            FileWriter writer = new FileWriter(file);
            System.out.print("Writing raw... ");
            write(records, writer);
        } finally {
            // comment this out if you want to inspect the files afterward
            file.delete();
        }
    }

    private static void writeBuffered(List<String> records, int bufSize) throws IOException {
        File file = File.createTempFile("foo", ".txt");
        try {
            FileWriter writer = new FileWriter(file);
            BufferedWriter bufferedWriter = new BufferedWriter(writer, bufSize);

            System.out.print("Writing buffered (buffer size: " + bufSize + ")... ");
            write(records, bufferedWriter);
        } finally {
            // comment this out if you want to inspect the files afterward
            file.delete();
        }
    }

    private static void write(List<String> records, Writer writer) throws IOException {
        long start = System.currentTimeMillis();
        for (String record: records) {
            writer.write(record);
        }
        // writer.flush(); // close() sh