difference between interface of a class and API java code example

Example: difference between class and interface in java

A class can be instantiated by 
creating its objects.
An interface is
never instantiated as the methods 
declared inside an interface are abstract
and does not perform any action, 
  so there is no use of instantiating any
interface.
A class is declared using a keyword class. 
In the same way, an interface is 
created using a keyword interface.
The members of a class can have 
access modifier like public, private, protected.
But the members of an interface
are always public as they have to be accessed 
by the classes implementing them.
The methods inside a class are 
  defined to perform an action on the fields
declared in the class. 
The methods inside an interface are purely abstract.
A class can implement any number 
of interfaces but can extend only one 
super class.
An interface can extend any number
of interfaces but cannot implement any
interface.
A class has constructors defined inside
it to get the variable initialized.
But, an interface does not have any
constructors as there are no fields 
to be initialized. The fields of an
interface are initialized 
at the time of their declaration only.