Explain overloading and overriding?

Method Overloading:
Method Overloading is a Compile time polymorphism. In method overloading, more than one method shares the same method name with different signature in the class. In method overloading, return type can or can not be be same, but we must have to change the parameter because in java, we can not achieve the method overloading by changing only the return type of the method.
Example of method overloading:

class MethodOverloadingEx{  
   static int add(int a, int b){return a+b;}  
   static int add(int a, int b, int c){return a+b+c;}  
 
    public static void main(String args[]) {
      System.out.println(add(4, 6));
      System.out.println(add(4, 6, 7));
    }
} 

Output:

//Here, add with two parameter method runs
10 

// While here, add with three parameter method runs 
17 

Method Overriding:
Method Overriding is a Run time polymorphism. In method overriding, derived class provides the specific implementation of the method that is already provided by the base class or parent class. In method overriding, return type must be same or co-variant (return type may vary in same direction as the derived class

Example of method overriding:

class Animal{  
      void eat(){System.out.println("eating.");}  
      }  
    class Dog extends Animal{  
    void eat(){System.out.println("Dog is eating.");}  
     }  
   class MethodOverridingEx{  
    public static void main(String args[]) {
      Dog d1=new Dog();
      Animal a1=new Animal();
      d1.eat();
      a1.eat();
    }
} 

Output:

// Derived class method eat() runs
Dog is eating

// Base class method eat() runs
eating