Question 1

HashMap is thread-safe whereas Hashtable is not10, Which of the following assignment statements is invalid?

double D = 45456.444;
long L = 45784;
int I = L;
int J = (int) D;

Answer

Correct Option: C

Question 2

Assume the following method is properly synchronized and called from a thread A on an object B: wait(2000); After calling this method, when will the thread A become a candidate to get another turn at the CPU?

java

After object B is notified, or after two seconds
After the lock on B is released, or after two seconds
Two seconds after object B is notified
Two seconds after lock B is released.

Answer

Correct Option: A

Question 3

for(Object obj: expression) { } What interface must the ?expression? implement in order for you to use it with enhanced for loop construct?

java

Iterator
Map
Enumeration
Iterable

Answer

Correct Option: D

Question 4

Which of the following are primitive types?

java

Float
None of the above
byte
String
integer

Answer

Correct Option: C

Question 5

What will happen when you attempt to compile and run the following code


public class Hope{
    public static void main(String argv[]){
        Hope h = new Hope();
    }
    protected Hope(){
        for(int i =0;
        i &lt;10;
        i ++){
            System.out.println(i);
        }
    }
}

java

Compilation and running with output 0 to 9
Run time error: Constructors cannot be declared protected
Compilation error: Constructors cannot be declared protected
Compilation and running with output 0 to 10
None of the above

Answer

Correct Option: A

Question 6

What is output of the above program?

Class conditional {
 public static void main(String args[]) {
  int i = 20;
  int j = 55;
  int z = 0;
  z = i &lt; j ? i : j; // ternary operator
  System.out.println("The value assigned is " + z);
 }
}

java

20
55
None of the above

Answer

Correct Option: A

Question 7

A class cannot be declared:

java

Static
Private
Default
None of the above

Answer

Correct Option: B

Question 8

Following code will result in:

int a1 = 5; 
double a2 = (float)a1;

java

Compilation error
Runtime error
No errors
Execptions

Answer

Correct Option: C

Question 9

Following code will result in:

class A {
  int b = 1;
  public static void main(String [] args) {
       System.out.println("b is " + b);
 }
}

java

Compilation error
Runtime Error
Runtime Exception
Output of b is 1

Answer

Correct Option: A

Question 10

Following code will result in:

class A { 
   public static void main(String [] args) {
       B b = new A(); 
   }
} 
class B extends A {}

java

Compilation error
Runtime Error
Runtime Exception
Other Execptions

Answer

Correct Option: A

Description: Java Programming Language Quiz - 5
Number of Questions: 10
Created by: Aliensbrain Bot
Tags: java

Java Programming Language Quiz - 5

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