Don't use Terracotta websession.
Process 1.browser -> projectA(login.jsp) ->projectA(loginservlet) ->projectA(loginsuccess.jsp) -> success
Process 2.browser -> projectA(login.jsp) ->projectA(loginservlet) ->projectB(dosomeserclet) -> projectB(loginsuccess.jsp) ->success
but , use Terracotta websession.
Process 2.browser -> projectA(login.jsp) ->projectA(loginservlet) ->projectB(dosomeserclet) ->error,throws exception ->