Unable to execute dex: multiple dex files define Lcom / facebook / android / AsyncFacebookRunner $ 1;

I have an android application that calls jar lib say b.jar. This is b.jar lib. then calls facebook sdk lib. When I compile my application in this situation, it always says

Unable to execute dex: multiple dex files define Lcom / facebook / android / AsyncFacebookRunner $ 1; Conversion to Dalvik format failed: dex cannot be executed: several dex files define Lcom / facebook / android / AsyncFacebookRunner $ 1;

I used several days to make it work, however I was not able to solve this problem. Does anyone know how to solve this problem?