Question 1

Question 1What are escape sequences in Java? Give three examples.

Accepted Answer

An escape sequence is a set of characters that has a special meaning to the Java compiler. In the escape sequence, a character is preceded by a backslash (\). Some examples of escape sequences are 
, \' and 	.

Question 2

Question 2What is the result of evaluating the following expression?  (1 + 2 * 2) / 2 + 2

Accepted Answer

(1 + 2 * 2) / 2 + 2 ⇒ (1 + 4) / 2 + 2⇒ (5) / 2 + 2⇒ 2 + 2⇒ 4

Question 3

Question 3What is a token in Java? Name the tokens available in Java.

Accepted Answer

All characters in a Java program are grouped into symbols called Tokens. As you know, a computer program consists of a set of instructions called statements. A statement is composed of various components. Each individual component of a programming statement is referred to as a token. Keywords, identifiers, Operators, Separators and literals are three tokens in Java.

Question 4

Question 4Why can't you use a keyword as a variable name?

Accepted Answer

Keywords are reserved words that have a special meaning to the Java compiler. As Java compiler reserves these words for its own use so they are not available as names for variables or methods.

Question 5

Question 5Which of the following are Java keywords?    input, class, public, int, x, y, radius

Accepted Answer

class, public, int are Java keywords.

Question 6

Question 6What are identifiers in Java? List three identifier formation rules.

Accepted Answer

Identifiers are used to name different parts of a program such as variables, methods, classes, objects, etc. Three identifier formation rules are:An an identifier can be a sequence of alphabets, digits, underscore and dollar sign characters only.Identifiers cannot start with a digit.An identifier must not be a Keyword or a Boolean or null literal.

Question 7

Question 7Explain the following statement — "In Java, total, Total, ToTaL, and TOTAL are all different identifiers."

Accepted Answer

Java is a case sensitive language. total, Total, ToTaL, and TOTAL have the same set of letters but they differ in the case of these letters. Therefore, Java considers each of them as a different identifier.

Question 8

Question 8How would you print characters like \, ' and " in Java?

Accepted Answer

We can print characters like \, ' and " using escape sequences i.e. preceding it with a backslash (\) symbol.

Question 9

Question 9Distinguish between the following:i. Token and Identifier

Accepted Answer

TokenIdentifierEach individual component of a programming statement is referred to as a token.Identifiers are fundamental building blocks of the program and are used to name different components of a program such as variables, methods and objects.Tokens in Java are categorised into 5 types — Keywords, Identifiers, Literals, Punctuators, Operators.Identifier is a type of token in Java.ii. Keyword and IdentifierKeywordIdentifierKeywords have a special meaning for Java compiler.Identifiers are used to name different components of a program such as variables, methods and objects.Keywords are reserved by the compiler for its own use.An identifier must not be a Keyword.iii. Character and String ConstantCharacter ConstantString ConstantCharacter Constants are written by enclosing a character within a pair of single quotes.String Constants are written by enclosing a set of characters within a pair of double quotes.Character Constants are assigned to variables of type char.String Constants are assigned to variables of type String.iv. Integer and float ConstantInteger ConstantFloat ConstantInteger Constants represent whole number values like 2, -16, 18246, 24041973, etc.Float Constants represent fractional numbers like 3.14159, -14.08, 42.0, 675.238, etc.Integer Constants are assigned to variables of data type — byte, short, int, long, charFloat Constants are assigned to variables of data type — float, double

Question 10

Question 10Distinguish between "A" and 'A'.

Accepted Answer

"A" is a string literal of length 1 containing the letter A in uppercase whereas 'A' is a character literal having value of A in uppercase.

Question 11

Question 11Describe primitive data types in Java.

Accepted Answer

Primitive data types are fundamental data types that are an integral part of the Java language and are used to declare a variable.

Question 12

Question 12List the size of primitive data types in Java.

Accepted Answer

Data TypeSize in Bytesbyte1short2int4long8float4double8char2boolean1

Question 13

Question 13Which integer and floating point data types take up the same number of bits in computer's memory?

Accepted Answer

Both, int and float take up 32 bits in memory. Similarly, both long and double take up 64 bits in memory.

Question 14

Question 14What is variable initialisation in Java? What are the default values of the following type of variables:short, int, long, float, double, and char.

Accepted Answer

Variable initialisation means assigning value to a variable for the first time. Below are the default values of the different data types:Data TypeDefault Valueshort0int0long0Lfloat0.0fdouble0.0dchar'\u0000'

Values and Data Types