https://diogomoreira.dev/tags/oop/Recent content in oop on Diogo MoreiraHugoen-USSun, 18 Feb 2024 00:00:00 +0000https://diogomoreira.dev/blog/sealed-and-final-in-java-17/Sun, 18 Feb 2024 00:00:00 +0000https://diogomoreira.dev/blog/sealed-and-final-in-java-17/<p>Java 17 brought the <strong>Sealed Classes</strong> feature, which allows greater control over how to structure a project&rsquo;s class hierarchy. In this post, we&rsquo;ll discuss this feature that permits classes and interfaces to have more control over their allowed subtypes.</p> <p>The keywords <code>sealed</code>, <code>non-sealed</code> and <code>permits</code> are the ones to be used in the syntax of sealed classes in Java. When we mark a class as <code>sealed</code>, it is as if we were marking it as <code>final</code>, which does not allow other classes to extend it. So, we add classes that can extend a sealed class with the help of <code>permits</code> keyword and then we list the permitted classes.</p>