The Fission Theory: This theory proposes that the Moon was once part of the Earth and somehow separated from the Earth early in the history of the solar system.
This provides modular approach to programming. Classes. A class is a concept used in object oriented programming languages such as C++, PHP, and JAVA etc. Apart from holding data, a class is also used to hold functions. An object is an instant of a class. In case of variables, the type is the class whereas the variable is the object.
1 Abstract classes can have methods with implementation whereas interface provides absolute abstraction and canât have any method implementations. 2  Abstract classes can have constructors but interfaces canât have constructors. 3  Abstract class have all the features of a normal java class except that we canât instantiate it.