In builder design pattern we removed the logic related to object constructor from client code & abstract it in separate class. This pattern was introduced to solve some of the problems with factory design pattern when the object contains a lot of attributes . major issues with factory design pattern is when object contains a lot of attributes. Some of the parameters might be optional but in factory pattern. we are forced to send all the parameters and optional parameters need to send as Null. Structure of Builder Pattern It has 4 main parts: Example : Builder design pattern Implementation 1.Car.java 2. Main.java