2.4_Understanding Data Types

Question 1

What are the two types categories of data in Java?

Answer 1

Primitive Types and Reference Types.

Question 2

How many built-in data types Java has?

Answer 2

Java has eight built-in data types, referred to as the Java primitive types.

Question 3

Which are the built-in data (primitive) types?

Answer 3

char | 16-bit Unicode value | ‘a’ | 0 to 65535
byte | 8-bit integral value | 123 | -128 to 127
short | 16-bit integral value | 25500 | -32768 to 32767
int | 32-bit integral value | 123 | -2,147,483,648 to 2,147,483,647
float |
long |

Question 4

Is String a Primitive?

Answer 4

No, it is not. String is often mistaken for a ninth primitive because Java includes built-in support for String literals and operators.

Question 5

Can reference types be assigned null?

Answer 5

Yes, which means they do not currently refer to an object.

Question 6

Can primitive types be assigned null?

Answer 6

No, If you attempt to assign them null value, compiler will give you an error.

Question 7

Which Data Type can call methods (Primitives | Reference)?

Answer 7

✅We can call a method on reference since it is of a reference type.
❌Primitives do not have methods.

Question 8

Type names

Answer 8

Primitive types have lowercase type names.

All classes that come with Java begin with uppercase.