has a vs is a relationship in java code example

Example 1: is a relationship in java

‘is a’ relationship is also known as inheritance. We can implement 
‘is a’ relationship or inheritance in java using extends keyword. 
The advantage of inheritance or is a relationship is reusability of code 
instead of duplicating the code.
  
Ex : 
Motor cycle is a vehicle
Car is a vehicle 
Both, car and motorcycle extends vehicle.

Example 2: is a and has a relationship in java

class Apple extends Fruit {

}

Example 3: is a and has a relationship in java

class Room {

    Table table = new Table();

}