HTTP post/API request works when sent from CURL on bash, fails from Apache http
Use form url-encoding for the data in the body with the content-type application/x-www-form-urlencoded :
CloseableHttpClient client = HttpClients.createDefault();HttpPost post = new HttpPost("https://accounts.spotify.com/api/token");post.setHeader(HttpHeaders.CONTENT_TYPE, "application/x-www-form-urlencoded");post.setHeader(HttpHeaders.AUTHORIZATION, "Basic " + encoded);StringEntity data = new StringEntity("grant_type=client_credentials");post.setEntity(data);HttpResponse response = client.execute(post);