Core Java - Interview Questions and Answers for 'Method' | Search Interview Question - javasearch.buggybread.com
Javasearch.buggybread.com

Search Interview Questions


 More than 3000 questions in repository.
 There are more than 900 unanswered questions.
Click here and help us by providing the answer.
 Have a video suggestion.
Click Correct / Improve and please let us know.
Label / Company      Label / Company / Text

   



Core Java - Interview Questions and Answers for 'Method' - 117 question(s) found - Order By Newest

next 30
 Q1. How can we run a java program without making any object?Core Java
Ans. By putting code within static method. With Java 6 and earlier versions, even static block can be used.

  Sample Code for static block

 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     Asked in 3 Companies      basic        frequent

Try 1 Question(s) Test


 Q2. What are the advantages and disadvantages of static variables and static methods ?Core Java
Ans. Advantages

Can do meta object operations ( like validating something before creating objects , keep count of number of objects )

Can do operations which have nothing to do with objects but still you want them to be tied to Class.

Disadvantages

Commonly used to static variables sometime leads to problems due to access by different objects.

Are not tied to objects so doesn't reflect pure Object Oriented approach.

Needs to be synchronized so as to avoid update conflicts by mutiple objects and threads.

Some limitation in testing as not all frameworks have facility to mock them. Powermock has but Mockito doesnt

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

   Like         Discuss         Correct / Improve     java   static   static variables   static methods


Very frequently asked. Favorite question in Walk in Drive of many Indian service companies.
  Q3. What is a final method ?Core Java
Ans. Its a method which cannot be overridden. Compiler throws an error if we try to override a method which has been declared final in the parent class.

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

   Like         Discuss         Correct / Improve     java   oops   final   final method     Asked in 30 Companies      basic        frequent

Try 1 Question(s) Test


Frequently asked to fresh graduates and less experienced.
 Q4. Why do we write public static void main ? Can we use some other syntax too for main ?Core Java
Ans. 1. public is the access modifier that makes the method accessible from anywhere, static is the keyword that makes it accessible even without creating any object, void means it doesn't return anything , String args[] is the array of argument that the method receives.

2. If we use main without the string args , it will compile correctly as Java will treat it as just another method. It wont be the method "main" which Java looks for when it looks to execute the class and hence will throw

Error: Main method not found in class , please define the main method as:
public static void main(String[] args)

3. Main is not a keyword but a special string that Java looks for while initiating the main thread.

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

   Like         Discuss         Correct / Improve     java   main method     Asked in 4 Companies      basic        frequent

Try 1 Question(s) Test


 Q5. Which of the following are valid declarations

1. void method(int... x){};
2. void method(int.. x){};
3. void method(int.. .x){};
4. void method(int ...x){};
5. void method(int... x){};
6. void method(int ... x){};
7. void method(int x, int... y){};
8. void method(int... x, int y){};
9. void method(int... x,int... y){};
Core Java
Ans. 1st is a valid and standard declaration.

2nd results in compilation error as only 2 dots are there.

3rd results in compilation error as three dots are not consecutive and broken.

4 through 6 may not be standard and ideal way of declarations but they are valid and will compile and work fine.

7 is valid declaration.

8 and 9 will result in compilation error as var args can only be provided to last argument.

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

   Like         Discuss         Correct / Improve     var args  methods  functions   method declaration  scjp  ocjp


 Q6. Which of the following is false about main method ?

a. It should be declared public and static
b. it should have only 1 argument of type String array
c. We can override main method
d. We can overload main method
Core Java
Ans. We can override main method

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

   Like         Discuss         Correct / Improve     java   main method


 Q7. Can we have multiple main methods in a single class ?Core Java
Ans. We can overload the main method by specifying different argument types. For example -

2 main methods with different arguments is perfectly legal

public static void main();
public static void main(String[] args);

The following are not legal as compiler will complain of duplicate methods

public static void main(String[] args);
public static void main(String[] args);

Even The following are not legal as we cannot overload on return types

public static String main(String[] args);
public static void main(String[] args);

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

   Like         Discuss         Correct / Improve     main method     Asked in 2 Companies


 Q8. Why can't we have diamond problem with interfaces ?Core Java
Ans. Interfaces don't have member elements and method definitions that could cause diamond problem. With Java 8, Interfaces have default method definitions. This could have created diamond problem but Java introduced a compile time check for "duplicate default methods" in case same method is derived from multiple interfaces and no definition is overridden by the class.

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

   Like         Discuss         Correct / Improve     diamond problem  interfaces  java 8  default methods


 Q9. Can we access instance variables within static methods ?Core Java
Ans. Yes.we cannot access them directly but we can access them using object reference.Static methods belong to a class and not objects whereas non static members are tied to an instance. Accessing instance variables without the instance handler would mean an ambiguity regarding which instance the method is referring to and hence its prohibited.

 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     Asked in 1 Companies


 Q10. Difference between parameters and arguments ?Core Java
Ans. Parameters are the variables that the method is expected to receive along with the method call. Arguments are the values which are passed on while calling the methods.

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

   Like         Discuss         Correct / Improve     parameter   argument   method   function   parameter vs argument      basic


 Q11. What is the difference between these two method declarations ?

private static void method(String[] arg)

and

private static void method(String... arg)
Core Java
Ans. First expects the argument as a string array whereas second expects variable number of string arguments or a string array.

So we can call both by providing string array as an argument but second can be called with 0 to n string arguments which cannot be done for first.

for example - We can call second method with any of following

method();
method("Hello");
method("Hello","World");
method(new String[4]);


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

   Like         Discuss         Correct / Improve     var args  methods  method declarations  functions


 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. Can we overload main method in Java ?Core Java
Ans. Yes, but the overloaded main methods without single String[] argument doesn't get any special status by the JVM. They are just another methods that needs to be called explicitly.

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

   Like         Discuss         Correct / Improve     java   main method   overloading   yes-no     Asked in 6 Companies      intermediate        frequent


 Q15. Can we override compareTo method for Enumerations ?Core Java
Ans. No. compareTo method is declared final for the Enumerations and hence cannot be overriden. This has been intentionally done so that one cannot temper with the sorting order on the Enumeration which is the order in which Enum constants are declared.

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

   Like         Discuss         Correct / Improve     java   compareto   final methods   enum   enumeration      expert


 Q16. 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


 Q17. Can we overload method as following ?

void method(int... x){};
void method(int[] x){};
Core Java
Ans. No. Because java internally treats var args as arrays and hence both method declarations will generate the same byte code and hence would result in ambiguity while determining call binding.

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

   Like         Discuss         Correct / Improve     var args  methods  functions   method declaration  scjp  ocjp


 Q18. What is a Final Method ?Core Java
Ans. A Method that cannot be overriden in the sub class.

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

   Like         Discuss         Correct / Improve     java   oops   java keywords   final   final method   overriding   basic interview question      basic        frequent

Try 1 Question(s) Test


 Q19. 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


 Q20. What does String intern() method do?Core Java
Ans. intern() method keeps the string in an internal cache that is usually not garbage collected.

Moreover provide reference for scp object for corresponding string object present in heap memory.

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

   Like         Discuss         Correct / Improve     java   string class   string   intern method   garbage collection   advanced     Asked in 2 Companies      expert


 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. Does java allow implementation of multiple interfaces having Default methods with Same name and Signature ?Core Java
Ans. No. Compilation error.

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

   Like         Discuss         Correct / Improve     java   java8   default method   yes-no     Asked in 1 Companies      intermediate


  Q23. What are Default Methods ?Core Java
Ans. With Java 8, We can provide method definitions in the Interfaces that gets carried down the classes implementing that interface in case they are not overridden by the Class. Keyword "default" is used to mark the default method.

  Sample Code for interface default

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

   Like         Discuss         Correct / Improve     java   java8   default methods     Asked in 7 Companies      expert        frequent


 Q24. 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


 Q25. 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


  Q26. How are values passed in Java ? By value or reference ?Core Java
Ans. Java only provides pass by value.

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

   Like         Discuss         Correct / Improve     ebay   pass by value   pass by reference   method call   methods   functions   function call     Asked in 10 Companies      basic        frequent


Recently asked in Capital One.
 Q27. What will happen if we call perform(null) ?

public void perform(Object obj) {
System.out.println("Object");
}

public void perform(Integer int) {
System.out.println("Integer");
}
Core Java
Ans. compiler will throws error as ambiguous methods

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

   Like         Discuss         Correct / Improve     overloading   method overloading     Asked in 1 Companies      intermediate


 Q28. What was the driving force to introduce default methods in Interfaces wef from Java 8 ?Core Java
Ans. Earlier any class implementing an interface was supposed to implement all methods declared in an interface. There was no place for optionally implementing all or subset of methods.Though we have abstract classes wherein we could have provided such a mechanism by declaring some methods as abstract while providing definition for some. But as Abstract classes have a body and are comparatively heavier than interfaces and interfaces associate closely to the concept of providing interfacing than abstract classes, Java might have though of providing optional implementation for default methods. This way same interface can be reused in variety of ways rather than making copies of an interface to suit different needs.

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

   Like         Discuss         Correct / Improve     java 8   java8  interface default methods  default methods     Asked in 6 Companies


 Q29. Can we override wait() or notify() methods?Core Java
Ans. wait and notify are declared final in object class and hence cannot be overridden.

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

   Like         Discuss         Correct / Improve     object class methods  wait  notify


 Q30. Can we overload abstract methods ?Core Java
Ans. Yes

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

   Like         Discuss         Correct / Improve     overloading  abstract methods  overloading abstract methods


next 30

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

Any input from you will be highly appreciated and It will unlock the application for 10 more requests.

Company Name:
Questions Asked: