(a) Which of the following are valid comments ?

The valid comments are:

Option 1 — /*comment*/
Option 3 — //comment

(b) What is meant by a package ? Name any two java Application Programming Interface packages.

A package is a named collection of Java classes that are grouped on the basis of their functionality. Two java Application Programming Interface packages are:

1. java.util
2. java.io

(c) Name the primitive data type in Java that is:

1. a 64-bit integer and is used when you need a range of values wider than those provided by int.
2. a single 16-bit Unicode character whose default value is '\u0000'.

1. long
2. char

(d) State one difference between the floating point literals float and double.

float literals	double literals
float literals have a size of 32 bits so they can store a fractional number with around 6-7 total digits of precision.	double literals have a size of 64 bits so they can store a fractional number with 15-16 total digits of precision.

(e) Find the errors in the given program segment and re-write the statements correctly to assign values to an integer array.

int a = new int (5);
for (int i=0; i<=5; i++) a[i]=i;

Corrected Code:

int a[] = new int[5];
for (int i = 0; i < 5; i++)
    a[i] = i;