Keywords

Question 1

static

Answer 1

• defines class members
• shared across all instances
• Static members are globally available to all instances of a class. So if it is changed in. a part, it changes for all of them.
• A word of caution: a static method can only use other static members within the same class.

Question 2

final

Answer 2

• declares something immutable (cannot be changed)
• primitive vars can’t modify values
• reference vars can’t switch references
• methods can’t be overridden
• classes can’t be extended

Question 3

abstract

Answer 3

• incomplete, missing definition

- an abstract class can’t be instantiated, only extended

Question 4

child class

Answer 4

• if a child class extends an abstract class, it must override all inherited abstract methods to provide an implementation of its own
• If you do not do this, the subclass must also be declared abstract – it’s not complete yet

Question 5

static vs instance members

Answer 5

a static member is shared class-wide while an instance member is associated with a single instance.