Sawaal
  • Home/
  • Searching for st

 Searching for "st"

Q:

What is static initializer block? What is its use?

Answer

A static initializer block is a block of code that declares with the static keyword. It normally contains the block of code that must execute at the time of class loading. The static initializer block will execute only once at the time of loading the class only.

Report Error

View answer Workspace Report Error Discuss

Subject: Java

Q:

What are the restrictions when overriding a method ?

Answer

Overridden methods must have the same name, argument list, and return type (i.e., they must have the exact signature of the method we are going to override, including return type.)


The overriding method cannot be less visible than the method it overrides( i.e., a public method cannot be override to private).


The overriding method may not throw any exceptions that may not be thrown by the overridden method

Report Error

View answer Workspace Report Error Discuss

Subject: Java

Q:

What is the difference between array and ArrayList ?

Answer

Array is collection of same data type. Array size is fixed, It cannot be expanded.


 


But ArrayList is a growable collection of objects.ArrayList is a part of Collections Framework and can work with only objects.

Report Error

View answer Workspace Report Error Discuss

Subject: Java

Q:

How will you define an abstract class?

Answer

An abstract class is defined with the keyword abstract Eg:
public abstract class MyClass { }

Report Error

View answer Workspace Report Error Discuss

Subject: Java

Q:

What is an abstract class?

Answer

An abstract class is an incomplete class. An abstract class is defined with the keyword abstract . We cannot create an object of the abstract class because it is not complete. It sets a behavioral protocol for all its child classes.

Report Error

View answer Workspace Report Error Discuss

Subject: Java

Q:

What is the difference between a constructor and a method?

Answer

A constructor is a member function of a class that is used to create objects of that class. It has the same name as the class itself, has no return type, and is invoked using the new operator. We cannot invoke a constructor directly.


 


A method is an ordinary member function of a class. It has its own name, a return type (which may be void), and is invoked using the dot operator.

Report Error

View answer Workspace Report Error Discuss

Subject: Java

Q:

The following SQL is which type of join: SELECT CUSTOMER_T. CUSTOMER_ID, ORDER_T. CUSTOMER_ID, NAME, ORDER_ID FROM CUSTOMER_T,ORDER_T ;

A) Equi-join B) Natural join
C) Outer join D) Cartesian join
 
Answer & Explanation Answer: D) Cartesian join

Explanation:
Report Error

View Answer Report Error Discuss

Filed Under: Database

Q:

If no multivalued attributes exist and no partial dependencies exist in a relation, then the relation is in what normal form?

A) First normal form B) Second normal form
C) Third normal form D) Fourth normal form
 
Answer & Explanation Answer: B) Second normal form

Explanation:
Report Error

View Answer Report Error Discuss

Filed Under: Database