Are static variables inherited

This is not exactly inheritance, its more like sharing having access to the static attribute of the class you are extending unless you are hiding it by declaring the same identifier in you subclass, note that in case of instance attribute if you change the value of the inherited attribute it will be changed in the super instance which was instantiated for your object but if there is another hierarchy which will be supposedly blind to your hierarchy it will not be affected.

In the case of static the parent attribute will be changed and any other hierarchy will take this effect too.

Please have a look into the documentation of oracle: http://docs.oracle.com/javase/specs/jls/se8/html/jls-8.html#d5e12110

Static variables are inherited as long as they're are not hidden by another static variable with the same identifier.

"Inherited" is not an ideal description of what is happening; a better way to describe it would be to say that static variables are shared among the subclasses of the base class.

All derived classes obtain access to static variables of their base classes. This includes protected variables, mirroring the situation with variables that are inherited.

The concept of hiding applies as well: when a class-specific variable str appears in the Child class, it hides the str variable of the parent class.

Note that the variable str of the base class does not become inaccessible: Child can still access it by fully qualifying with the name of Parent class.