Perl の標準エラー出力を Process.getErrorStream() で読むとブロックしてしまう

import java.io.*;

public class RedirTester {

    public static void main(String[] args) throws IOException {
        Runtime runtime = Runtime.getRuntime();
        String[] cmdArray = new String[] { "perl.exe", "-c", "-w" };
        Process process = runtime.exec(cmdArray, null, null);

        OutputStream outputStream = process.getOutputStream(); // stdin of perl.exe
        BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(outputStream), 0x1000);
        writer.write("faor ($i = 0; $i < 10; $i++)\n" // Perl の文法をわざと間違えている。
        + "{\n"
        + "    print $i;\n"
        + "}\n");
        writer.close();

        InputStream inputStream = process.getErrorStream(); // stderr of perl.exe
        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream), 0x1000);
        while (true) {
            String line = reader.readLine(); // ここでブロックしてしまう。
            if (line == null) {
                break;
            }
            System.out.println(line);
        }
        reader.close();
    }
}