我的类的GZIPOutputStream问题扩展了OutputStream

Question

我有以下问题。我写了Stream类，它扩展了OutputStream。这是代码：

import java.io.IOException;
import java.io.OutputStream;

public class ToUpperLetterOutputStream extends OutputStream {
    public OutputStream outputStream;

    public ToUpperLetterOutputStream(OutputStream outputStream)
    {
        this.outputStream =  outputStream;
    }

    @Override
    public void write(int b) {
        char ch  = toUpper((char)b);
        try {
            outputStream.write((int)ch);
        } catch (IOException e) {
            System.err.println("IO ERROR");
        }
    }

    protected char toUpper(int b)
    {
        char ch = (char)b;
        if (Character.isLowerCase(b))
        {
            ch = Character.toUpperCase(ch);
        }

        return ch;
    }
}

现在我正在尝试将流与GZIPOutputStream一起使用：

    byte[] bytes = stringBuilder.toString().getBytes();

    try (
            GZIPOutputStream g =  new GZIPOutputStream( new ToUpperLetterOutputStream(
                    new FileOutputStream("result"))))  {

                    g.write(bytes, 0, bytes.length);
                    g.finish();

    } catch (FileNotFoundException e) {
        System.err.println("Nie znaleziono pliku");
    } catch (IOException e) {
        System.err.println("IO Error");
    }

程序运行正常，但是当我尝试解压缩结果文件时，出现以下异常：

java.util.zip.ZipException: invalid literal/lengths set
at java.util.zip.InflaterInputStream.read(InflaterInputStream.java:164)
at java.util.zip.GZIPInputStream.read(GZIPInputStream.java:117)
at java.io.FilterInputStream.read(FilterInputStream.java:107)
at Test.decompressGzipFile(Test.java:36)
at Test.main(Test.java:50)

当我不使用Stream时，解压缩效果很好。为什么会发生这种情况，我应该进行哪些更改以使此代码正确？