Why are protected variables not allowed by default in Checkstyle?

Question

I get a lot of warnings in eclipse like these:

Variable \'myVariable\' must be private and have accessor methods.

I think I get

Answer 1

Theoretically, protected attributes (variables) are an anti-pattern in object-oriented languages. If only subclasses need to access member attributes of its superclass, define the attributes themselves as private and create protected accessor methods (getter and setter). This approach applies the concept of 'information hiding'. There is an alternative solution: define protected immutable (final) member attributes.

Further readings:

• Should you ever use protected member variables?
• http://www.codinghorror.com/blog/2006/08/properties-vs-public-variables.html