How to get the rainbow contacts users in android

I cant able to get the rainbow contacts users list, I can run command rbw users and check the users list. It shows the list. Still im facing a problem to get the users list in android SDK. 

ArrayItemList<IRainbowContact> m_roster = new ArrayItemList<>();

m_roster = RainbowSdk.instance().contacts().getRainbowContacts();

we are collecting this contacts inside updatecontact method in ContactsTabAdapter

Please suggest and guide me, where im going wrong.