New Features in Java 17
Manoj Kumar
Principal Consultant | BFSI |AWS Certified Solutions Architect|Core Java | J2EE | Spring Boot| Microservice | Elasticsearch | Redis | Kafka | OAuth2 | DevOps | AWS Cloud | Kubernetes | Certified ACTICO | Security Audit
In this article, I will share the Java SE 17 new features and changes. Java 17 LTS is the long-term support release for the Java SE platform. It was released on September 15, 2021.
First, there are many JDK Enhancement Proposals (JEPs) in Java 17. I mention them in order of JEP numbers, you can see the list below:
As for now, let’s analyze the changes and new features in each iteration of Java, that are most important from the perspective of most of us Java Developers.
Record: Records are very useful for immutable data carrier classes.?
Let’s declare a Record as BankAccount below:
With the record declaration above, we automatically define:
We can also do the following for the records;
Sealed Classes
The sealed classes?permit their subclasses to extend them. The other classes cannot extend the parent if they are not permitted an extension by the parent class.?The sealed interfaces?permit the subinterfaces and implementing classes.?All permitted classes or interfaces in the “permits list” must be declared as final and they needed to be located in the same package
Text Blocks
Let’s start with the Text blocks definition. Text Blocks are blocks of String that can be declared by starting with three double quotes “”” which can be followed by a line break and closed by three double quotes again. We can use newlines and quotes inside the text blocks without taking care of escape line break characters and in this way it will be much easier and readable to work with JSON, SQL, and similar texts with text blocks.
Text blocks can be used to keep a reasonably readable JSON or XML template in your code. External files are still likely a better idea, but it’s still a nice option to do it in pure Java if necessary.
Switch Expressions
?is present in a lot of languages, but over the years it got less and less useful because of the limitations it had. Other parts of Java grew,?but the switch?did not. Nowadays?switch?cases can be grouped much more easily and in a more readable manner (note there’s no?break!) and the?switch?expression itself actually returns a result.
Even more, can be achieved with the new?yield?keyword that allows returning a value from inside a code block. It’s virtually a?return?that works from inside a case block and sets that value as a result of its?switch. It can also accept an expression instead of a single value. Let’s take a look at an example:
Context-Specific Deserialization Filters
As everyone knows, deserializing the data from untrusted data is dangerous and should not be a best practice. Java 9, enabled software engineers to validate incoming serialized data from untrusted sources to prevent security issues. Java 17, allows applications to configure context-specific and dynamically selected deserialization filters defined at the JVM level.
Vector API (Second Incubator)
Java 17, leverages specialized CPU hardware that supports vector instructions and allows the execution of such instructions as pipelines. This improves the Vector API performance and also adds other enhancements like support operations on characters, translating byte vectors to and from boolean arrays, etc.
If you are starting a project from scratch and thinking about a Java version to use might want to consider Java 17, as it’s more secure and contains useful features. It’s also an LTS release that has a longer support period, so it might be considered a future-proof option. To decide one must also think about dependencies in the project if any of the frameworks planned to use support Java 17 release.