no, Parent class can not access the members of child class ,but child class can access members of parent class

Of course. ALL classes in Java are the child of another class. Even ones which don't appear to be, actually are a child of the master Object class.

child a=new child();

Method overriding is similar to method overloading, with a small difference. In overriding, a method in a parent class is overridden in the child class. The method in the child class will have the same signature as that of the parent class. Since the method in the child class has the same signature & name as the method of its parent class, it is termed as overriding. In situations where you may have to explicitly call the parent class method you can use the "super" keyword and for explicitly calling the current objects method you can use the "this" keyword.

it depends on who the child is and if you have hurt that child teased that child and things like that