Sending HTTP DELETE request in Android

The problematic line is con.setDoOutput(true);. Removing that will fix the error.

You can add request headers to a DELETE, using addRequestProperty or setRequestProperty, but you cannot add a request body.

This is a limitation of HttpURLConnection, on old Android versions (<=4.4).

While you could alternatively use HttpClient, I don't recommend it as it's an old library with several issues that was removed from Android 6.

I would recommend using a new recent library like OkHttp:

OkHttpClient client = new OkHttpClient();Request.Builder builder = new Request.Builder()    .url(getYourURL())    .delete(RequestBody.create(        MediaType.parse("application/json; charset=utf-8"), getYourJSONBody()));Request request = builder.build();try {    Response response = client.newCall(request).execute();    String string = response.body().string();    // TODO use your response} catch (IOException e) {    e.printStackTrace();}

getOutputStream() only works on requests that have a body, like POST. Using it on requests that don't have a body, like DELETE, will throw a ProtocolException. Instead, you should add your headers with addHeader() instead of calling getOutputStream().