- fixes a potential NPE in corehttpProvider

Author: baywet

src/main/java/com/microsoft/graph/http/CoreHttpProvider.java

@@ -361,6 +361,9 @@ public Request authenticateRequest(Request request) {
 						return request;
 					}
 				}).newBuilder();
+				if(this.connectionConfig == null) {
+					this.connectionConfig = new DefaultConnectionConfig();
+				}
 				okBuilder.connectTimeout(connectionConfig.getConnectTimeout(), TimeUnit.MILLISECONDS);
 				okBuilder.readTimeout(connectionConfig.getReadTimeout(), TimeUnit.MILLISECONDS);
 				okBuilder.followRedirects(false);