ALTAS import fails when AtlasClient is used but succeeds when curl is using in Knox trusted proxy setup

Atlas client to call import for hive databases. We have a knox based trusted proxy setup when this call fails with 500 Internal Sever Error. But the same exact call succeeds when curl is used in place of atlas java client. 

I debugged this and found that Atlas client doesn't set  "Expect", "100-continue" header and curl automatically sets this. I have a patch where i added this header in the atlas client java code and post that it works fine. 

Let me know if anybody has any specific questions.