In instantiating the ImmutableString, the function pointers to the get and length methods actually refer to the String.get and String.length method, by going through the base variable which is an internally stored String object. The use of a function pointer can achieve inheritance of a method from a superclass.
Most women will start to show at some point between weeks 12 and 24 of pregnancy, with most reporting that they began to show during the first half of their second trimester, between 12 and 18 weeks.
Less than 12 weeks or in the first trimester, the uterus is still hidden inside the pubic bone. While the fact that the uterus stays low until the second trimester, there is no exact time when the abdomen will start showing pregnancy. It depends on your body type and how many pregnancies you have had.