Data Types And Variables — Part 2 MCQs with Explanations

floating-point numbers are by default of type double. 99.9 is a double not a float. To print "float" cast 99.9 to (float)

Static variable have a single copy of memory. That means all the objects will share the same memory location. So, if the object test increase the value of x by 1, then object test1 will access that incremented value of x

lossy conversion from int to short x = x*5; ^ 1 error

Instance variable is unique for their object, that means each copy of memory for variable i will be available for each object. So, changing value of i from one object will not affect the value of i accessed by another object. 1. Two objects of the Test class, t1 and t2 , are created using the new keyword. 2. The default value of the instance variable i is 34 as defined in the class Test . 3. The instance variable i of t1 is then set to 65 using t1.i = 65; 4. When we print t1.i , it will output 65 . 5. When we print t2.i , it will output 34 . This is because t2 is a separate instance of the Test class, and its i remains the default value of 34 . Therefore, the correct output will be 6534 .

By default, a boolean variable will contain false.

The result of 1/4 will be zero because integer division is carried out on the operands. If you need to obtain a fractional value you need to use either a float or double literal as in 1F / 4F.

Global and static variable need not be initialized before use. Default value of global and static int variable is zero. Default value of boolean variable is false. Remember local variable must be initialized before use.

$7 is valid identifier. Identifiers must start with a letter, a currency character ($), or underscore ( _ ). Identifiers cannot start with a number. You can't use a Java keyword as an identifier. do is a Java keyword.

By placing a zero in front of the number is an integer in octal form. 010 is in octal form so its value is 8

int or smaller expressions always resulting in an int. So compiler complain about Type mismatch: cannot convert from int to byte for b = b+7; But b += 7; // No problem because +=, -=, *=, and /= will all put in an implicit cast. b += 7 is same as b = (byte)b+7 so compiler not complain.

byte can only hold up to 127. So compiler complain about possible loss of precision. static byte MAX_VALUE − This is constant holding the maximum value a byte can have, 2 7 -1. static byte MIN_VALUE − This is constant holding the minimum value a byte can have, -2 7 .

i and j are instance variable and attempting to access an instance variable from a static method. So Compilation fails.

Range of byte data in java is -128 to 127. But byte data type in java is cyclic in nature.

Here's an explanation of the code: 1. The class Test is defined with an instance variable a initialized to 10. 2. The method method is defined within the Test class, which takes an integer parameter a . 3. Inside the method method, the local variable a shadows the instance variable a because they have the same name. 4. The value of the local variable a is incremented by 1 using the += operator, making it 4. 5. The value of the local variable a is then incremented again using the pre-increment operator ++ , making it 5. 6. The value of the local variable a (which is 5) is printed using System.out.println() . 7. In the main method, an instance of the Test class is created. 8. The method method is invoked on the t object with the argument 3. 9. This triggers the execution of the method method, which prints 5 as explained above. Therefore, the output of the code is 5 . Thus, option B is the correct answer.

The given Java code initializes a variable g with the value 3 . It then uses the pre-increment operator ( ++ ) on g before multiplying it by 8 and printing the result using System.out.print . The expression ++g * 8 is evaluated as follows: ++g increments the value of g to 4 . 4 * 8 is equal to 32 . Therefore, the output of the code will be 32 .

The correct answer is D: Compilation error . Here's why: In Java, variables have a scope, which determines where they can be accessed in the code. 'x' is declared outside the inner block, so it's accessible both inside and outside the curly braces {}. 'y' is declared inside the inner block {}. This means 'y' is only accessible within that block. The line 'System.out.println(x + " " + y);' is outside the inner block where 'y' is defined. Therefore, the compiler will give an error because it cannot find a variable named 'y' in that scope. The program will not compile because of the scope issue with the variable 'y'.

Prints 2.5 is the correct answer to “The following fraction of code double STATIC = 2.5 ; System.out.println( STATIC );”. This question is standard in competitive examination syllabi for Data Types And Variables.

34 S is the correct answer to “What would be the output of the following fraction of code? int Integer = 34 ; char String = 'S' ; System.out.print( Integer ) ; System.out.print( String ) ;”. This question is standard in competitive examination syllabi for Data Types And Variables.

A Boolean literal is the correct answer to “In Java, the word true is ................”. This question is standard in competitive examination syllabi for Data Types And Variables.

Enum is the correct answer to “Which class does all the Enums extend”. This question is standard in competitive examination syllabi for Data Types And Variables.

Precision is the correct answer to “Which of the following is the advantage of BigDecimal over double”. This question is standard in competitive examination syllabi for Data Types And Variables.

0.009999999999999998 0.01 is the correct answer to “What will be the output of the following Java code snippet? double a = 0.02; double b = 0.03; double c = b - a; System.out.println(c); BigDecimal _a = new BigDecimal("0.02"); BigDecimal _b = new BigDecimal("0.03"); BigDecimal _c = b.subtract(_a); System.out.println(_c);”. This question is standard in competitive examination syllabi for Data Types And Variables.

-32768 to 32767 is the correct answer to “What is the range of short data type in Java”. This question is standard in competitive examination syllabi for Data Types And Variables.

False is the correct answer to “Is SimpleDateFormat thread safe”. This question is standard in competitive examination syllabi for Data Types And Variables.

keyword is the correct answer to “Which of these can not be used for a variable name in Java”. This question is standard in competitive examination syllabi for Data Types And Variables.

True is the correct answer to “Are enums are type-safe”. This question is standard in competitive examination syllabi for Data Types And Variables.

BigDecimal is the correct answer to “Which of the below data type doesn't support overloaded methods for +,-,* and /”. This question is standard in competitive examination syllabi for Data Types And Variables.

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-mm-dd"); sdf.parse(new Date()) is the correct answer to “How to convert a String to a Date object”. This question is standard in competitive examination syllabi for Data Types And Variables.

static variable with value 1 on scale 0 is the correct answer to “What is BigDecimal.ONE”. This question is standard in competitive examination syllabi for Data Types And Variables.

* operator has converted b * 50 into int, which can not be converted to byte without casting is the correct answer to “What will be the error in the following Java code? byte b = 50; b = b * 50;”. This question is standard in competitive examination syllabi for Data Types And Variables.

True & False is the correct answer to “Which of these values can a boolean variable contain”. This question is standard in competitive examination syllabi for Data Types And Variables.

double is the correct answer to “If an expression contains double, int, float, long, then the whole expression will be promoted into which of these data types”. This question is standard in competitive examination syllabi for Data Types And Variables.

5.0 is the correct answer to “What will be the output of the following Java program? class dynamic_initialization { public static void main(String args[]) { double a, b; a = 3.0; b = 4.0; double c = Math.sqrt(a * a + b * b); System.out.println(c); } }”. This question is standard in competitive examination syllabi for Data Types And Variables.

Integer or Boolean is the correct answer to “Which of these can be returned by the operator &”. This question is standard in competitive examination syllabi for Data Types And Variables.

double is the correct answer to “Which data type value is returned by all transcendental math functions”. This question is standard in competitive examination syllabi for Data Types And Variables.

public prototype( ) is the correct answer to “What is the prototype of the default constructor of this Java class? public class prototype { }”. This question is standard in competitive examination syllabi for Data Types And Variables.

1 2 3 is the correct answer to “What will be the output of the following Java program, if we run as "java main_arguments 1 2 3"? class main_arguments { public static void main(String [] args) { String [][] argument = new String[2][2]; int x; argument[0] = args; x = argument[0].length; for (int y = 0; y < x; y++) System.out.print(" " + argument[0][y]); } }”. This question is standard in competitive examination syllabi for Data Types And Variables.

-3.4e+038 is the correct answer to “Which of these literals can be contained in float data type variable”. This question is standard in competitive examination syllabi for Data Types And Variables.

Compilation Error is the correct answer to “What will be the output of the following Java code? class A { final public int calculate(int a, int b) { return 1; } } class B extends A { public int calculate(int a, int b) { return 2; } } public class output { public static void main(String args[]) { B object = new B(); System.out.print("b is " + b.calculate(0, 1)); } }”. This question is standard in competitive examination syllabi for Data Types And Variables.

Compilation Error is the correct answer to “What will be the output of the following Java code snippet? enum Levels { private TOP, public MEDIUM, protected BOTTOM; }”. This question is standard in competitive examination syllabi for Data Types And Variables.