Can we read a file using BufferedReader and write the content to another file using BufferedOutputStream? and vice versa

I am learning about java io concepts and I need to clarify a doubt about it.

I am trying to read a file using a reader like BufferedReader and write the same to OutputStream like BufferedOutputstream. Here is a sample of my code.

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileReader;

public class ReaderToStream
{
    public static void main(String[] args)throws Exception 
    {
        BufferedReader br = new BufferedReader(new FileReader(new File("f1.txt")));
        BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(new File("f2.txt")));
        
        int ch = 0;
        
        while((ch=br.read())!=-1)
        {
            bos.write(ch);
        }
        
        
        bos.close();
        br.close();
    }
}

I know that reader reads in characters and the output stream writes in bytes, but how can we handle it perfectly, because when my file has normal English characters, there is no problem, but when I have symbols or other language characters(for example காலை வணக்கம், 早上好) it copies the text to some random text(like æ©ä`好).

can anyone help me to understand the topics clearly in-depth?

Thanks for any help, and sorry if asked anything stupid.

You can use an adapter design pattern implementation called OutputStreamWriter.

An OutputStreamWriter is a bridge from character streams to byte streams

Your code snippet using this class, looks like the code below:

BufferedReader br = new BufferedReader(new FileReader("f1.txt"));
OutputStreamWriter out = new OutputStreamWriter(
    new BufferedOutputStream(new FileOutputStream("f2.txt"))
);     
int ch;
while ((ch = br.read()) != -1) {
    out.write(ch);
}
br.close();
out.close();

Also, u can specify an encoding:

Charset oneWay = Charset.forName("UTF-8");
Charset anotherWay = StandardCharsets.UTF_8;
OutputStreamWriter out1 = new OutputStreamWriter(..., oneWay);
OutputStreamWriter out2 = new OutputStreamWriter(..., anotherWay);