How To Get Java Equivalent Of C++ Constant

How to make sure that a variable passed to a method isn't altered by the method? I know in C++ you can do something like

void aMethod(const Object &item) {
........
}

I know that you can stop a variable from being reinitialized in java by doing this

void aMethod(final Object item) {
.........
}

However, that won't stop it from calling a setter on the item or changing something in it. Is there some other keyword out there that can do this? I just found that java DOES recognize the const keyword but that it really is useless.

So, any practical way that const can be further approximated in java beyond using final?