Chapter 5

Question 1

What is “NoClassDefFoundError” error

Answer 1

If java filename given wrong in execution

Question 2

What is “NoSuchMethdError” error

Answer 2

main error

Question 3

What is “can not resolve symbol” error

Answer 3

variable or method does not exists

Question 4

What is null pointer exception

Answer 4

Variable not pointing to anything

Question 5

What is the basic purpose of inheritance

Answer 5

Reuse

Question 6

Java support which inheritance

Answer 6

Single inheritance

Question 7

Does all functions are virtual

Answer 7

Yes

Question 8

What is super keyword in java

Answer 8

The super keyword in java is a reference variable which is used to refer immediate parent class object.

Question 9

What is type casting

Answer 9

Conversion of data type

Question 10

What is upcasting

Answer 10

We take small data type to big data type

Question 11

What is downcasting

Answer 11

We take large data type to small data type e.g. double -> int. There is chance of loss of information. We need to tell explicitly.