Generics

Question 1

What is the purpose of generics in Java?

Answer 1

To enable generic algorithms to be written, and types to be defined at a later time.

Question 2

Which OOP principle does generics enable?

Answer 2

Polymorphism.

Question 3

How does generics enable safer programs?

Answer 3

Because types are checked at compile time rather than run time.

Question 4

What are 2 main advantages of Generics?

Answer 4

• Reduces the need for type casting.
• Enables compile time checking of java types.

Question 5

What is the difference between compile time and run time errors?

Answer 5

Compile time usually refers to semantic and syntactical errors. Run-time usually is due to code breakage. Thus, run time is more severe and costly.

Question 6

What does it mean that generics are non reifiable?

Answer 6

They are not all completely available at run time due to type erasure.

Question 7

Define Heap Pollution…

Answer 7

A situation in which a variable of a parameterised type refers to a variable of the wrong type, thus causing an unchecked warning.