ArrayList is a class

Extending one class and implementing one more class

 Which keywords are used to define an abstract class 

Which class is the superclass of all Adapter classes?

Which of the following methods belongs to the string class

Which of this keyword can be used from preventing overriding of methods?

Which of these data type is returned by every method of OutputStream?

Which keyword is used by a class to implement an interface defined previously?

Which of the following statements contains only unimplemented methods?

What happens when a class implements two interfaces that define the same variable?