How to Create Immutable Class in Java
Creating Immutable Class in Java: Best Practices
How to Create Immutable Class in Java
In Java, an immutable class is a class whose instances cannot be modified after they are created. This is usually achieved by making the class final, making its fields private and final, and not providing any setter methods. Immutable classes have several advantages, such as simplifying concurrent programming, ensuring thread safety, and guaranteeing that objects will not be modified unintentionally. By creating immutable classes, you can also promote cleaner code and reduce the risk of bugs.
To Download Our Brochure: https://www.justacademy.co/download-brochure-for-free
Message us for more information: +91 9987184296
1 - Define the class as final: To create an immutable class in Java, start by declaring the class as final. This prevents other classes from extending it and modifying its behavior.
2) Declare all fields as private: Encapsulate the class fields by declaring them as private. This ensures that they cannot be accessed directly from outside the class.
3) Do not provide setter methods: Omit setters for the class fields to prevent external modification of the object's state. Instead, provide constructor initialization or getter methods for access.
4) Initialize fields only once: Assign values to the class fields only in the constructor or using initializer blocks. Avoid setting the fields outside of these methods to maintain immutability.
5) Make fields final: Declare the class fields as final to ensure that once they are assigned a value, they cannot be changed. This guarantees the immutability of the class.
6) Return copies in getter methods: If the class contains mutable objects, return copies of these objects in getter methods instead of returning references to the original objects. This prevents external modifications.
7) Ensure immutability in methods: Make sure that methods within the class also maintain the immutability of the object. Avoid any operations that modify the state of the object or its fields.
8) Override equals and hashCode methods: If necessary, override the equals and hashCode methods to properly handle comparisons for immutable objects. Implement these methods based on the class fields.
9) Consider implementing Serializable: If the immutable class needs to be serialized, implement the Serializable interface and provide compatibility with serialization mechanisms in Java.
10) Document immutability in the class: Include clear documentation in the class to indicate that it is immutable. This helps developers understand the intended usage and behavior of the class.
11) Test the immutability: Write test cases to ensure that the class behaves as expected and maintains immutability in various scenarios. This helps validate the correctness of the implementation.
12) Use static factory methods: Consider using static factory methods to create instances of the immutable class instead of relying solely on constructors. This provides more flexibility in object creation.
13) Implement defensive copying: If the class contains mutable objects as fields, implement defensive copying to ensure that external modifications do not affect the internal state of the class.
14) Avoid subclassing: As part of designing an immutable class, avoid allowing subclassing to prevent any modifications that could compromise the immutability of the class.
15) Follow best practices and design patterns: When creating immutable classes, adhere to established best practices and design patterns in Java programming to maintain consistency and readability in the codebase.
These points can serve as a comprehensive guide for training students on creating immutable classes in Java effectively.
Browse our course links : https://www.justacademy.co/all-courses
To Join our FREE DEMO Session: Click Here
Contact Us for more info:
- Message us on Whatsapp: +91 9987184296
- Email id: info@justacademy.co
Sap Abap Hana Interview Questions
