91. Iterating what we cannot have in a record

There are several artifacts that we cannot have in a Java record. Let’s tackle the top 5 one by one.

A record cannot extend another class

Since a record already extends java.lang.Record and Java doesn’t support multiple inheritances, we cannot write a record that extends another class:

public record MelonRecord(String type, float weight) 
  extends Cucurbitaceae {…}

This snippet doesn’t compile.

A record cannot be extended

Java records are final classes, so they cannot be extended:

public class PumpkinClass extends MelonRecord {…}

This snippet doesn’t compile.

A record cannot be enriched with instance fields

When we declare a record, we also provide the components that become the instance fields of the record. Later, we cannot add more instance fields as we could in a typical class:

public record MelonRecord(String type, float weight) {
  private String...