Java static class

Question

While reading the hibernate docs I've seen several times the use of static classes.

As an example here is an excerpt of the code in the documentation:

@Entity(name = "SystemUser")
public static class SystemUser {

    @EmbeddedId
    private PK pk;

    private String name;

    //Getters and setters are omitted for brevity
}

@Embeddable
public static class PK implements Serializable {

    private String subsystem;

    private String username;

    public PK(String subsystem, String username) {
        this.subsystem = subsystem;
        this.username = username;
    }

    private PK() {
    }

    @Override
    public boolean equals(Object o) {
        if ( this == o ) {
            return true;
        }
        if ( o == null || getClass() != o.getClass() ) {
            return false;
        }
        PK pk = (PK) o;
        return Objects.equals( subsystem, pk.subsystem ) &&
                Objects.equals( username, pk.username );
    }

    @Override
    public int hashCode() {
        return Objects.hash( subsystem, username );
    }
}

I thought top level static classes where not allowed in Java. What is the reason for indicating this classes as static?

**"I thought top level static classes where not allowed in Java"** why ? — c0der, Jun 02 '18 at 11:17
*The modifier static pertains only to member classes, not to top level or local or anonymous classes* - [JLS](https://docs.oracle.com/javase/specs/jls/se10/html/jls-8.html#jls-8.1.1). These static classes in docs should be a part of some enclosing class in this case. — Oleksandr Pyrohov, Jun 02 '18 at 11:34
@c0der after reading about the topic is what I understand, like https://stackoverflow.com/questions/7486012/static-classes-in-java or as pointed out by Oleksandr — wallek876, Jun 02 '18 at 13:16

Java static class

0 Answers0