Java5

Question 1

What is a parameterized or generic type?

Answer 1

generic type is a generic class or interface that is parameterized over types.

Question 2

Can we use parameterized types in exception handling?

Answer 2

no

Question 3

What is a wildcard parameterized type?

Answer 3

? extends A

Question 4

What is Autoboxing and what are its advantages/pitfalls?

Answer 4

primitive types => corresponding wrapper classes
pitfalls- comparison, npe

Question 5

Problems Enum type solves
(comparing to “public static int” enum pattern)

Answer 5

list of constants, singleton

Question 6

Can we add something to List> ?

Answer 6

no

Question 7

What are Annotations and which predefined by the language specification
does one know

Answer 7

annotation is metadata.
(@Deprecated, @Override, @SuppressWarnings)

Question 8

How to create custom annotation? What is retention type?

Answer 8

public @interface A{}
retention type - when annotations will be visible
CLASS, SOURCE, RUNTIME

Question 9

What is Lambda expression ? (Java 8)

Answer 9

anonymous methods used to implement a method defined by a functional interface

Question 10

What is method reference ? (Java 8)

Answer 10

static method ref
instance method ref
constructor ref

Question 11

What is default metod ? (Java 8)

Answer 11

interface methods with implementation