Use the following syntax: super.myMethod(); To call a constructor of the superclass, just call super() in the first line of the subclass's constructor, passing any required parameters.

If you assign a superclass object to a variable of a subclass's data type, you need to do explicit casting. For example: Object a; Customer b; b = (Customer) a; When you assign a subclass to a variable having a supeclass type, the casting is performed automatically.

Java doesn't support mutiple inheritance because of 'Diamond problem'. The 'diamond problem' is an ambiguity that can occur when a class multiple intehertis from two classes that both descend from a common superclass.

A static variable is associated with the class as a whole rather than with specific instances of a class. Each object will share a common copy of the static variables i.e. there is only one copy per class, no matter how many objects are created from it. Class variables or static variables are declared with the static keyword in a class. These are declared outside a class and stored in static memory. Class variables are mostly used for constants. Static variables are always called by the class name. This variable is created when the program starts and gets destroyed when the programs stops. The scope of the class variable is same an instance variable. Its initial value is same as instance variable and gets a default value when its not initialized corresponding to the data type. Similarly, a static method is a method that belongs to the class rather than any object of the class and doesn't apply to an object or even require that any objects of the class have been instantiated.
     Static methods are implicitly final, because overriding is done based on the type of the object, and static methods are attached to a class, not an object. A static method in a superclass can be shadowed by another static method in a subclass, as long as the original method was not declared final. However, you can't override a static method with a non-static method. In other words, you can't change a static method into an instance method in a subclass.