Fixes ambiguous error codes

library/src/main/java/com/okta/oidc/net/HttpResponse.java

@@ -111,11 +111,28 @@ public JSONObject asJson() throws IOException, JSONException {
                 mStatusCode >= HttpURLConnection.HTTP_MULT_CHOICE) {
             throw new HttpStatusCodeException(mStatusCode, mHttpClient.getResponseMessage());
         }
-        InputStream is = getContent();
-        if (is == null) {
+        return getJsonObjectFromResponseInputStream(getContent());
+    }
+
+    public JSONObject asJsonWithErrorDescription() throws IOException, JSONException {
+        if (mStatusCode < HttpURLConnection.HTTP_OK ||
+                mStatusCode >= HttpURLConnection.HTTP_MULT_CHOICE) {
+            try {
+                return getJsonObjectFromResponseInputStream(getContent());
+            } catch (Exception any) {
+                throw new HttpStatusCodeException(mStatusCode, mHttpClient.getResponseMessage());
+            }
+        }
+        return getJsonObjectFromResponseInputStream(getContent());
+    }
+
+    private static JSONObject getJsonObjectFromResponseInputStream(
+            final InputStream inputStream
+    ) throws IOException, JSONException {
+        if (inputStream == null) {
             throw new IOException("Input stream must not be null");
         }
-        BufferedReader reader = new BufferedReader(new InputStreamReader(is));
+        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
         Writer writer = new StringWriter();
         String line = reader.readLine();
         while (line != null) {

library/src/main/java/com/okta/oidc/net/request/TokenRequest.java

@@ -128,7 +128,7 @@ public TokenResponse executeRequest(OktaHttpClient client) throws AuthorizationE
         TokenResponse tokenResponse;
         try {
             response = openConnection(client);
-            JSONObject json = response.asJson();
+            JSONObject json = response.asJsonWithErrorDescription();
             if (json.has(AuthorizationException.PARAM_ERROR)) {
                 try {
                     final String error = json.getString(AuthorizationException.PARAM_ERROR);

library/src/test/java/com/okta/oidc/clients/sessions/SessionClientImplTest.java

@@ -232,7 +232,8 @@ public void refreshTokenFailure() throws InterruptedException {
         latch.await();
         assertNull(cb.getResult());
         assertNotNull(cb.getException());
-        assertEquals(cb.getException().getMessage(), "Invalid status code 401 Client Error");
+        assertEquals(cb.getException().getMessage(), "No client credentials found.");
+        assertEquals(cb.getException().type, TYPE_OAUTH_TOKEN_ERROR);
     }
 
     @Test