Java 记录与 Kotlin 数据类

Question

Java 14 offers a new feature called Records , helping to create javabeans.

I've been using Kotlin for a couple of times, and of course, Java Records remind me Data Classes .

Are they completely similar? Or are there fundamental differences between them apart from the languages syntaxes?

Answer 1

This is a great article about all those differences.

In summary:

Similarities

• generated methods: equals , hashCode , toString
• generated constructor
• generated getters (but Kotlin getter is called o.name , while Java uses o.name() )
• can modify the canonical constructor
• can add additional methods

Differences

Kotlin's data classes support many other little things:

data class (Kotlin)	record (Java)
copy method for easier object creation	no copy method
variables can be var or val	variables can only be final
can inherit from other non-data classes	no inheritance
can define non-constructor mutable variables	can define only static variables

Both are great for reducing the code bloat.