My EyE

1. Avoid creating unnecessary objects. Object creation is the more expensive operation in java.So, Create an objects when its required, public class Student {     private List students;     public List getStudents() {         if(students == null) {             students = new ArrayList();         }         return students;     } } 

Factory pattern comes from creational design pattern category.main objective of this pattern is to instantiate an object and Factory pattern interface is responsible for creating objects but the sub-classes desides which class to instantiate. Im going to start with a simple example.Suppose an application asks for entering the name and sex of a person. If the sex is Male (M), it displays welcome message saying Hello Mr. <Name> and if the sex is Female (F), it displays message saying Hello Ms <Name>. First Im going to create a Person class.. public class Person {     public String name;     public String gender;     public String getName() {         return name;     }     public String getGender() {     ...