Revise paste Untitled

import javax.annotation.processing.SupportedSourceVersion;
import java.io.*;
import java.util.logging.Filter;

public class Main {

public static void main(String[] args){
        BufferedInputStream bis = null;
        BufferedOutputStream bos = null;
        try {
            InputStream in = new FileInputStream("izvor.txt");
             bis = new BufferedInputStream(in);
            OutputStream out = new FileOutputStream("destinacija.txt");
             bos = new BufferedOutputStream(out);

byte[] b = new byte[bis.available()];
            int at = 0;
            for(int x = bis.read(); x != -1; x = bis.read()) {
                if(x == 10) {
                    if(b[0] >= 48 && b[0] <= 57) {
                        for(int j = 0; j < at; j++) {
                            out.write(b[j]);
                        }
                        out.write(10);
                    }
                    at = 0;
                }
                else {
                    b[at] = (byte) x;
                    at++;
                }
            }
            if(b[0] >= 48 && b[0] <= 57) {
                for(int j = 0; j < at; j++) {
                    out.write(b[j]);
                }
            }
            out.flush();
        }
        catch (IOException ex ){

}
        finally {
            try {
                if(bis != null)
                  bis.close();
                if(bos != null)
                 bos.close();

}
            catch (IOException e) {

}
        }
    }
}