Why getter and setter are better than public fields in Java? Example (original) (raw)

public modifier vs getter and setter method in Java

Providing getter and setter method for accessing any field of class in Java may look unnecessary and trivial in the first place, simply because you can make field publicand it’s accessible from everywhere in Java program. In fact, many programmers do this in their early days but once you start thinking in terms of enterprise application or production code, you will start seeing how much trouble it can create in terms of maintenance.

Since as per the SDLC process, software spends more time in maintenance than development, it’s worth keeping ease of maintenance as one of the goals in development. In reality using getter and setter method in Java is one of the Java coding best practices much like using @Override annotation while the overriding method in Java.

Main problem with making field public instead of getter and setter is that it violates Encapsulationby exposing the internals of a class. Once you are exposed internals of class you can not change internal representation or make it better until making changes in all client codes.

Since every code change comes with risk and the cost of regression testing is high during maintenance, its not a good idea to make the field public in Java. In this Java tutorial, we will see some more benefits getter and setter offers over public fields in Java.

What is the getter and setter method in Java?

For those who are new to Java and not very familiar with Java terminology, getter and setter method means a method for accessing and modifying any property of a class in Java. For example in Counter class if we have a count variable than getCount() is getter method and setCount(int count) is a setter method in Java. Let’s see How much difference decision of making properties of class public makes over providing getter and setter method in Java.

getter and setter method gives you centralized control on how a the particular field is initialized and provided to the client which makes the validation and debuggingmuch easier. you can simply put breakpoints or print statement to see which thread are accessing and what values are going out.

On the validation front, you can easily avoid an incorrect value for a particular field, i.e. if the field is non-nullable then you can throw NullPointerException or IllegalArgumentException. with the public field, your client code will break when it starts using that field without knowing which part of your code is setting incorrect or null value.

By making fields private and providing getter and setter and following java bean naming convention you make your class usable with many open-source libraries and framework e.g. display tag. which uses a combination of reflection and Java bean naming convention to dynamically load and access fields.
with getter and setter you give an opportunity to Subclass to override these methods and return what makes more sense in the context of sub class.

Though I agree it makes code more verbose and there are certainly cases where the use of public field make sense. As we said by making a class field public violates Encapsulationbut what if the Class in question is a private nested class or package-private class, In that case, they are well encapsulated and giving getter and setter can be avoided if you are not doing any validation and simply setting and getting value.

Even in the worst case if requirement changes come and you need to perform sophisticated validation you can do this because all client code is within your reach.

So this was one of the best coding practices to follow on Java. Always try to make the field private and final unless otherwise, you have a very good reason not to do so. making fields private and providing getter and setter are standard Java coding standards and allows your code to be compatible with other frameworks which use reflection.

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