oop quiz 1

What is the size of an integer variable?

Options:

• 16 bit

• 128 bit

• 32 bit

• 8 bit

• 64 bit

32 bit

Does garbage collection guarantee that a program will not run out of memory?

Options:

• True

• False

False

What is the output of the code snippet below? If there is no output, answer "no output". If there is an error, answer "error".

int i=0; boolean t=true; boolean f=false,b; b=(t & ((i++)==0)); b=(f & ((i+=2)>0)); System.out.print(i);

3 (due to bit-wise operators)

Which of the following lines of code will compile without error? (Choose all that apply)

Options:

• boolean i=true, j=false; if(i && j) System.out.println("OK");

• boolean b=true; if(b) System.out.println("So true");

• int i=2, j=2; if(i==1 | j==2) System.out.println("OK");

• int i=0; if(i) System.out.println("Hello");

a, b, & c

Which of the following are legal identifiers? (Choose all that apply)

Options:

• _whatavariable

• variable2

• 2variable

• $2

• #myvar

• for

• ___

• if

_whatavariable, variable2, $2, ___

What is the output of the code snippet below? If there is no output, answer "no output". If there is an error, answer "error".

boolean x=true; int a; if(x)     a = x ? 1 : 2; else     a = x ? 3: 4; System.out.print(a);

1

What is an applet?

Options:

• It is a Java program that runs in a Web browser

• It is a tool

• It is a run time environment

• It is a stand-alone Java program

• It is an IDE

It is a Java program that runs in a Web browser

It is possible to force garbage collection in Java.

Options:

• True

• False

False

Primitive variables are stored on stack.

Options:

• True

• False

True

What is the output of the code snippet below? If there is no output, answer "no output". If there is an error, answer "error".

boolean a[] = new boolean[10]; for(int i=5; i<=10 ; i++)     System.out.print(a[i]);

error

When an object is passed as a parameter to a method, a copy of the object is created.

Options:

• True

• False

False

Local variables are automatically assigned a default value if not explicitly initialized.

Options:

• True

• False

False

What is the output of the code snippet below? If there is no output, answer "no output". If there is an error, answer "error".

int i=0; boolean t=true; boolean f=false, b; b=(t && ((i++)==0)); b=(f && ((i+=2)>0)); System.out.print(i);

1 (skips evaluating 2nd b, due to false condition)

What is the output of the code snippet below? If there is no output, answer "no output". If there is an error, answer "error".

int i=5; if(i==5){     int j=10, j+=i; } System.out.println(j);

error, j is not initialized prior to if-condition. After traversing if-condition, j will not exist outside the if-condition, and the print function incurs an error.

Which of the following lines will compile without warning or error?

Options:

• short s = 900000; char c = 10;

• float f = 2.5; boolean b = "true";

short s = 900000; char c = 10;

What is the output of the code snippet below?

int temp=1, temp2=0, ans=0, num=5; for(int i=1; i<= num; i++){     ans = temp + temp2;     temp = temp2;     temp2 = ans;     System.out.print(ans + " "); }

1 1 2 3 5

What is the output of the code snippet below? If there is no output, answer "no output". If there is an error, answer "error".

int i=1; switch(i) {     default: System.out.println("default");     case 0: System.out.println("zero");             break;     case 1: System.out.print("one");     case 2: System.out.print("two"); }

onetwo

A byte can be of what size

Options:

• -128 to 127

• (-2 power 8)-1 to 2 power 8 depends on the particular implementation of the Java Virtual Machine -255 to 256

-128 to 127

Which of the following are legal definitions of the main method that can be used to execute a class?

Options:

• public static void Main(String[] args)

• public static int main(String args[])

• public static void main(string args[])

• Public static void main(String args[])

• public static void main(String args[])

• public static void main(String *args)

• static public void MAIN(String[] args)

• public void main(String args)

public static void main(String args[])

What is the output of the code snippet below? If there is no output, answer "no output". If there is an error, answer "error".

int x=0, y=1, z; if(x) z=0; else z=1; if(y) z=2; else z=3; System.out.print(z);

error

It is possible to change the contents of a String object.

Options:

• True

• False

False

Which of the following is not a keyword in Java?

Options:

• public

• private

• void

• Boolean

• static

Boolean

What will happen when you attempt to compile and run this code?

public class Main{     public static void main(String argv){         System.out.println("Hello world");     } }

Options:

• The code will compile but will complain at run time that main is not correctly defined

• The code will compile but will complain at run time that no constructor is defined

• The compiler will complain that main is a reserved word and cannot be used for a class

• The code will compile and when run will print out "Hello world"

The code will compile but will complain at run time that main is not correctly defi