org.apache.catalina.connector.CoyoteOutputStream cannot be cast to java.io.ByteArrayOutputStream

This error occurs when you try to cast a CoyoteOutputStream object to a ByteArrayOutputStream object. The CoyoteOutputStream class is a subclass of ServletOutputStream, which is used to write binary data to the output stream. On the other hand, the ByteArrayOutputStream class is used to write data to a byte array.

To solve this error, you need to use the appropriate class for the task you are performing. If you need to write binary data to the output stream, use the CoyoteOutputStream class. If you need to write data to a byte array, use the ByteArrayOutputStream class.

Here's an example of how to use the CoyoteOutputStream class:

response.setContentType("application/octet-stream");
response.setHeader("Content-Disposition", "attachment; filename=file.bin");
ServletOutputStream out = response.getOutputStream();
out.write(data);
out.flush();
out.close();

And here's an example of how to use the ByteArrayOutputStream class:

ByteArrayOutputStream baos = new ByteArrayOutputStream();
baos.write(data);
byte[] bytes = baos.toByteArray();

Make sure you are using the correct class for the task at hand to avoid the "cannot be cast" error.