Core Java - Interview Questions and Answers for 'Static' | Search Interview Question

Interview Questions and Answers - Order By Newest

Q11. Can we serialize static variables ?

Ans. No. Only Object and its members are serialized. Static variables are shared variables and doesn't correspond to a specific object.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve serialization java oops static static variables Asked in 1 Companies intermediate rare}

Try 2 Question(s) Test

Q12. How can we create objects if we make the constructor private ?

Core Java

Ans. We can do so through a static public member method or static block.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java oops static constructor static method static block private Asked in 1 Companies}

Q13. Similarity and Difference between static block and static method ?

Core Java

Ans. Both belong to the class as a whole and not to the individual objects. Static methods are explicitly called for execution whereas Static block gets executed when the Class gets loaded by the JVM.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java oops static static method static block difference between similarity basic frequent}

Try 1 Question(s) Test

Q14. Will the static block be executed in the following code ? Why ?

class Test
{
static
{
System.out.println("Why I am not executing ");
}
public static final int param=20;
}

public class Demo
{
public static void main(String[] args)
{
System.out.println(Test.param);
}
}

Ans. No the static block won't get executed as the referenced variable in the Test class is final. Compiler replaces the content of the final variable within Demo.main method and hence actually no reference to Test class is made.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java oops static static block final variable}

Try 1 Question(s) Test

Q15. In which cases , moving methods to utility class could be useful ?

Core Java

Ans. It could be worthy to move a method to util class if the method needs to be shared, doesn't require polymorphic behavior and need not be overridden in special cases.

Don't belong to one group through is-a relationship ( You can share through parent class method )

Don't implement a specific interface ( java 8 default methods )

Doesn't involve complex computing as you will be loosing the benefit of object state with just static method.

Doesn't require polymorphic behavior as static methods don't participate in runtime polymorphism.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve utility classes util classes static methods application design rare}

Q16. Can we override static methods ? Why ?

Core Java

Ans. No.

Static methods belong to the class and not the objects. They belong to the class and hence doesn't fit properly for the polymorphic behavior.

A static method is not associated with any instance of a class so the concept of overriding for runtime polymorphism using static methods is not applicable.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java oops static static methods java keywords yes-no intermediate frequent}

Q17. What is a Static import ?

Core Java

Ans. By static import , we can access the static members of a class directly without prefixing it with the class name.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java java5 static import static java keyword static import Asked in 4 Companies basic frequent}

Q18. Difference between nested and inner classes ?

Ans. Inner class is a type of nested class.

Inner classes are non static nested classes i.e the one that are associated with the instance of outer class.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java oops static nested classes inner classes nested vs inner class basic frequent}

Try 1 Question(s) Test

Q19. Difference between static vs. dynamic class loading?

Core Java

Ans. static loading - Classes are statically loaded with Java new operator.

dynamic class loading - Dynamic loading is a technique for programmatically invoking the functions of a class loader at run time.

Class.forName (Test className);

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java jvm memory management class loaders classloaders static class loading static loading dynamic class loading dynamic loading Asked in 2 Companies expert frequent}

Q20. Is it possible to compile and run a Java program without writing main( ) method?

Ans. Yes, it is possible by using a static block in the Java program.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java main static block compile yes-no}

Q21. Will the following program display ""Buggy Bread"" ?

class Test{
   static void display(){
      System.out.println(""Buggy Bread"");
   }
}

class Demo{
   public static void main(String... args){
      Test t = null;
      t.display();
   }
}

Core Java

Ans. Yes. static method is not accessed by the instance of class. Either you call it by the class name or the reference.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java static static method code}

Q22. Which of the following syntax is correct ?import static java.lang.System.*;or static import java.lang.System.*;

Core Java

Ans. import static java.lang.System.*;

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java static import generics import OCJP SCJP Oracle certified java developer Asked in 1 Companies}

Q23. Can we use static method definitions in Interfaces ?

Core Java

Ans. Yes, Effective Java 8.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java java8 static interface methods yes-no Asked in 1 Companies}

Q24. Why can't we use this in static context ?

Core Java

Ans. Static methods can be called using instance references wherein this would have made sense but static method can also be called using Class name wherein this would mean nothing and hence forbidden.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java static methods this keyword}

Try 2 Question(s) Test

Q25. Which of the following cannot be marked static ?

a. Constructors , Classes ( Outer ) , Classes ( nested ), Interfaces , Local variables , Inner Class methods and instance variables.
b. Constructors , Classes ( Outer ) , Interfaces , Local variables , Class variables , Class Methods , Inner Class methods and instance variables.
c. Constructors , Classes ( Outer ) , Interfaces , Local variables , Inner Class methods and instance variables.
d. Constructors , Classes ( Outer ) , Classes (Nested), Interfaces , Local variables , Inner Class methods and instance variables

Ans. Constructors , Classes ( Outer ) , Interfaces , Local variables , Inner Class methods and instance variables.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve oops java static nested classes static nested classes}

Try 2 Question(s) Test

Q26. What is the use of static keyword in Java ?

Core Java

Ans. static keyword is used to specify that the respective programming construct ( method , variable ) belongs to the class and not to its instance and is supposed to be shared by all instances of the class.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve static keyword Asked in 1 Companies basic frequent}

Q27. How can we ensure thread safety in static method ?

Core Java

Ans. By using synchronized static method or synchronized block

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve threads synchronization static methods Asked in 2 Companies intermediate}

Q28. Can static method access instance variables ?

Core Java

Ans. Though Static methods cannot access the instance variables directly, They can access them using instance handler.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve static static method java oop variables Asked in 1 Companies basic frequent}

Q29. Does java allow overriding static methods ?

Core Java

Ans. No. Static methods belong to the class and not the objects. They belong to the class and hence doesn't fit properly for the polymorphic behavior.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java oops static static method overriding intermediate}

Try 3 Question(s) Test

Q30. Explain static blocks in Java ?

Core Java

Ans. A static initialization block is a normal block of code enclosed in braces, { }, and preceded by the static keyword. Here is an example:

static {
// whatever code is needed for initialization goes here
}

A class can have any number of static initialization blocks, and they can appear anywhere in the class body. The runtime system guarantees that static initialization blocks are called in the order that they appear in the source code.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java oops static static block Asked in 16 Companies basic frequent}

Q31. Explain Static nested Classes ?

Ans. The accessibility (public, protected, etc.) of the static nested class is defined by the outer class.

A static nested class is not an inner class, it's a top-level nested class.

The name of the static nested class is expressed with OuterClassName.NestedClassName syntax.

When you define an inner nested class (or interface) inside an interface, the nested class is declared implicitly public and static.

Static nested classes can be declared abstract or final.

Static nested classes can extend another class or it can be used as a base class.

Static nested classes can have static members.

Static nested classes can access the members of the outer class (only static members, obviously).

The outer class can also access the members (even private members) of the nested class through an object of nested class. If you don't declare an instance of the nested class, the outer class cannot access nested class elements directly.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java oops nested classes static nested classes inner classes}

Q32. Can we use "this" within static method ? Why ?

Core Java

Ans. No. Even though "this" would mean a reference to current object id the method gets called using object reference but "this" would mean an ambiguity if the same static method gets called using Class name.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java oops static this keyword this yes no why questions intermediate}

Q33. What will happen if static modifier is removed from the signature of the main method?

Ans. Program throws "NoSuchMethodError" error at runtime .

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java main method main static static method nosuchmethoderror}

Q34. Will static block for Test Class execute in the following code ?

class Test
{
static
{
System.out.println("Executing Static Block.");
}
public final int param=20;

public int getParam(){
return param;
}
}

public class Demo
{
public static void main(String[] args)
{
System.out.println(new Test().param);
}
}

Ans. Yes.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java static static block final variable yes no}

Try 1 Question(s) Test

Q35. Can we access Interface static method using Interface references ?

Ans. No, only using Interface Name.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java java8 static interface methods}

Q36. Can we have default method with same name and signature in the derived Interface as the static method in base Interface and vice versa ?

Ans. Yes , we can do that as static methods are not accessible using references and hence cannot lead to conflict. We cannot do inverse as Default methods cannot be overridden with the static methods in derived interface.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java java8 default methods static interface methods}

Q37. Shouldn't we make a class with all static members is its just expected to be executed as a standalone program with just one thread. Moreover Lets assume that there is no runtime Polymorphism required and there is no need for serialization ?

Design

Ans. Still No in case we are making use of inheritance. we may have problem wherein we have program flow moving across common inherited method and specific methods of the derived class. call made to another static method in the parent class will only access the static class of the Parent class irrespective of the call from any of the derived class.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve static class static vs singleton inheritance}

Q38. Why is a constant defined as a static final in Java?

Core Java

Ans. Final makes sure that the value doesn't change after initialization and static makes sure that there is only one copy that can be shared across objects.

Making it non static will unnecessarily create a different copy per object wherein the same value will kept for all copies ( as its final and cannot be changed ).

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java static final variables variable constants basic frequent}

Q39. Can we initialize member variables within static block ?

Ans. Static block is like static method that gets executed upon class loading. The way static method allows accessing member variables ( using object references only ), the same static block can also access and initialize member variables.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java static block}

Q40. When are static and instance methods resolved ? During compile time or Runtime ?

Ans. Static methods are resolved during compile time and hence they cannot participate in runtime polymorphism. Instance methods are resolved during runtime.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java static methods methods runtime polymorphism intermediate}

Search Interview Questions

Help us and Others Improve. Please let us know the questions asked in any of your previous interview.