Java (anonymous or not) inner classes: is it good to use them?

Question

In some of my projects and in some books was said to not use inner class (anonymous or not, static or not) - except in some restricted conditions, like

Answer 1

Code without inner classes is more maintainable and readable. When you access private data members of the outer class from inner class, JDK compiler creates package-access member functions in the outer class for the inner class to access the private members. This leaves a security hole. In general we should avoid using inner classes.

Use inner class only when an inner class is only relevant in the context of the outer class and/or inner class can be made private so that only outer class can access it. Inner classes are used primarily to implement helper classes like Iterators, Comparators etc which are used in the context of an outer class.