Why is it necessary to define data type in Java programming?

Define the following with an example:

(a) variable

(b) constant

(c) boolean data type

(d) coercion

(e) primitive data type

(f) non-primitive data type

Explain the term type casting.

Assign the following to a variable with suitable data type.

(a) m = 22 / 7

(b) p= 1.4142135 (value of square root of 2)

(c) k= 0.00004545

(d) n=24.50