Question

Iam a Java beginner and i would like to ask whats the pros and cons about this:

If i make a Class and i wont write my own setters and getters i can just get and set my class’s properties like:

myClassInstance.name = "Jones"
myClassInstance.job = "Manager"

System.out.println(myClassInstance.name);
System.out.println(myClassInstance.job);

Why better if i make getters and setters and do like this:

myClassInstance.setName("Jones");
myClassInstance.setJob("Manager");

System.out.println(myClassInstance.getName());
System.out.println(myClassInstance.getJob());

Answer 1

This question is related to one of the basic principals of OO design: Encapsulation!

Accessors (also known as getters and setters) are methods that let you read and write the value of an instance variable of an object

public class AccessorExample {
private String attribute;

public String getAttribute() {
 return attribute;
}

public void setAttribute(String attribute) {
 this.attribute = attribute;
}
}

Why to use them?

Getter and Setters make APIs more stable. Lets consider a field public in a class which is accessed by other classes. Now later on, you want to add any extra logic while getting and setting the variable. This will impact the existing client that uses the API. So any changes to this public field will require change to each class that refers it. On the contrary, with accessor methods, one can easily add some logic like cache some data, lazily initialize it later. Moreover, one can fire a property changed event if the new value is different from the previous value. All this will be seamless to the class that gets value using accessor method.

Also Getters and setters methods allow different access levels – for eg. Get may be public, but the Set could be protected.