1.What is Method in java?

  • Method is a sub block of a class that contains logic of that class.
  • logic must be placed inside a method, not directly at class level, if we place logic at class level compiler throws an error.
  • So class level we are allowed to place variables and methods.
  • The logical statements such as method calls, calculations and printing related statements must be placed inside method, because these statements are considered as logic. 
  • For more information @ Methods in java



  1. package com.instanceofjava;
  2. class sample{
  3.  
  4. int a;
  5. int b;
  6.  
  7. System.out.println("instance of java"); // compiler throws an error.
  8.  
  9. }
  10.  

  1. package com.instanceofjava;
  2. class sample{
  3.  
  4. static int a=10;
  5.    
  6. public static void main(String args[]){

  7. System.out.println(a); // works fine,prints a value:10
  8.  
  9.  }
  10. }

2.What is meant by method overloading in java?


  • Defining multiple methods with same name is known as polymorphism.
  • Defining multiple methods with same name and with different arguments known as method overloading.

  1. package com.instanceofjava;
  2. class A{
  3.  
  4. public void show(int a){
  5. System.out.println("saidesh");
  6. }
  7.  
  8. public void show(int a,int b){
  9. System.out.println("ajay");
  10. }
  11.  
  12. public void show(float a){
  13. System.out.println("vinod");
  14. }
  15. public static void main(String args[]){
  16.  
  17. A a=new A();
  18.  
  19. a.show(10);
  20. a.show(1,2);
  21. a.show(1.2);
  22.  
  23. }
  24. }
Output:

  1. saidesh
  2. ajay
  3. vinod


3.What are the other names for method overloading?


  • Method overloading also known as static polymorphism or compile time polymorphism because at compile time itself we can tell which method going to get executed based on method arguments.
  • So method overloading also called as static binding. 

4.What are the basic rules of method overloading?

  • Defining a method with same name and differ in number of arguments
  • Defining a method with same name and differ in type of arguments
  • Defining a method with same name and differ in order of type of arguments
  • Return type of the method not involved in method overloading.

5.Can we overload static methods in java?

  • Yes. We can overload static methods in java.
  • Method overriding is not possible but method overloading is possible for static methods.
  • Before that lets see about method overloading in java.
  • lets see an example java program which explains static method overloading.
  1. class StaticMethodOverloading{
  2.  
  3. public static void staticMethod(){
  4.  
  5. System.out.println("staticMethod(): Zero arguments");
  6.  
  7.  
  8. public static void staticMethod(int a){
  9.  
  10. System.out.println("staticMethod(int a): one argument");
  11.  
  12.  
  13. public static void staticMethod(String str, int x){
  14.  
  15. System.out.println("staticMethod(String str, int x): two arguments");
  16.  
  17. }
  18.  
  19. public static void main(String []args){
  20.   
  21.   StaticMethodOverloading.staticMethod();
  22.   StaticMethodOverloading.staticMethod(12);
  23.   StaticMethodOverloading.staticMethod("Static method overloading",10);
  24.  
  25. }
  26. }


 Output:

  1. staticMethod(): Zero arguments
  2. staticMethod(int a): one argument
  3. staticMethod(String str, int x): two arguments


6.Can we overload main method in java?

Yes we can overload main method in java

Java Program to overload main method in java

  1. class mainMethodOverloading{
  2.  
  3. public static void main(boolean x){
  4.  
  5. System.out.println("main(boolean x) called ");
  6.  
  7.  
  8. public static void main(int x){
  9.  
  10. System.out.println("main(int x) called");
  11.  
  12.  
  13. public static void main(int a, int b){
  14.  
  15. System.out.println("main(int a, int b) called");
  16.  
  17. }
  18.  
  19. public static void main(String []args){
  20.    
  21.  
  22. System.out.println("main(String []args) called ");
  23.  
  24.   mainMethodOverloading.main(true);
  25.   mainMethodOverloading.main(10);
  26.  mainMethodOverloading.main(37,46);
  27.  
  28.  
  29. }
  30. }




 Output:

  1. main(String []args) called
  2. main(boolean x) called
  3. main(int x) called
  4. main(int a, int b) called

method overloading interview questions





7.Can we overload constructors in java?

  • Yes we can overload constructor in java

  1. package instanceofjava;
  2. class ConstructorChaining{
  3. int a,b 
  4. ConstructorChaining(){
  5. this(1,2);
  6.  System.out.println("Default constructor");
  7.  
  8.  
  9. ConstructorChaining(int x , int y){
  10.  
  11. this(1,2,3); 
  12. a=x;
  13. b=y;
  14.  System.out.println("Two argument constructor");
  15.  
  16. }
  17.  
  18. ConstructorChaining(int a , int b,int c){
  19.  System.out.println("Three argument constructor")
  20.  
  21. public static void main(String[] args){
  22.  
  23.  ConstructorChaining obj=new ConstructorChaining();
  24.   System.out.println(obj.a);
  25.   System.out.println(obj.b);
  26.  
  27. }
  28. }


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