Since Java 21, wrapper classes have played an increasingly sophisticated role in Java’s type system. Here’s everything you ...

Even the most complicated classes in Java can be flattened down to nothing more than the set of primitive data types they represent. But primitive types aren’t objects, and that presents a problem.

An example is String. This is not a primitive type in Java, but rather a reference type: in this case it “points” to a class that can have multiple values and methods.