ADDITIONAL SYSTEM INFORMATION :
java 17
windows 10

A DESCRIPTION OF THE PROBLEM :
[chunkedStreamingMode](https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/net/HttpURLConnection.html#setChunkedStreamingMode(int)) simply enables chunk streaming but it doesn't enforce the specified size on the chunks transmitted. It allows chunks of any size to be transmitted regardless of this value and it doesn't divide the data into multiple chunks if it exceeds this value. We have to do it manually

This method should divide the data in an write() call into chunks automatically without the user manually calculating the size of each chunk but it doesn't.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1) Create an simple server to print the chunks received from the client

2) Create an HttpURLConnection to transfer chunks of size greater than the specified value

3)Observe output on server end. chunk sizes can be of any length irrespective of the length specified in the client method



EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Upon transmitting 15 bytes of data and with setChunkedStreamingMode(5) the URL connection should transmit 3 chunks each of size 5 bytes and the last 0 chunk as follows. Output is viewed on the server side

POST /Test.txt HTTP/1.1
User-Agent: Java/17.0.2
Host: localhost:3000
Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2
Connection: keep-alive
Content-type: application/x-www-form-urlencoded
Transfer-Encoding: chunked



=========
5
01234

=========
5
56789

=========
5
ABCDE

=========
0




ACTUAL -
Full 20 bytes is transmitted as one chunk

POST /Test.txt HTTP/1.1
User-Agent: Java/17.0.2
Host: localhost:3000
Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2
Connection: keep-alive
Content-type: application/x-www-form-urlencoded
Transfer-Encoding: chunked


=========
f
0123456789ABCDE

==========
0

---------- BEGIN SOURCE ----------
Run server in an seperate JVM

class Server
{
 public static void main(String[] args)throws Exception
 {
  try(ServerSocket server=new ServerSocket(3000))
  {
   try(Socket client=server.accept())
   {
    try(InputStream input=client.getInputStream())
    {
     int length;
     byte[] data=new byte[6000];
     
     while((length=input.read(data))>0)
     {
      System.out.println(new String(data,0,length));
      System.out.println("=========");
     } 
    } 
   } 
  } 
 }
}

Run client in an seperate JVM

public class Chunked
{
 public static void main(String[] args) throws Exception
 {
  HttpURLConnection con=(HttpURLConnection)new URL("http://localhost:3000/Test.txt")
                        .openConnection();
  
  con.setChunkedStreamingMode(5);
  
  con.setDoOutput(true);
  try(OutputStream output=con.getOutputStream())
  {
   output.write("0123456789ABCDE".getBytes());
   output.flush();
  } 
 }
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
in the client we need to manually divide the data our self into equal sized chunks.  

FREQUENCY : always