Authenticate user from membership tables in Java

I have a asp.net web application which is using membership for authentication and authorization. Now I have d开发者_开发百科evelop the application in Java which authenticate the user from the same database [i.e. from the membership tables]. How to do that?

Many frameworks have a security "library" to abstract away the low level stuff. What framework are you using? If you aren't using one take a look at Spring and Spring Security.