I have the following entities:

```
@Entity
public class License  {

     // ...

    @OneToMany(mappedBy = "license", cascade = CascadeType.ALL, fetch = FetchType.EAGER, orphanRemoval = true)
    private Set<Service> services = new HashSet<>();

    // ...

    protected void setServices(Set<String> services) {
        this.services.clear();
        if (services != null) {
            this.services.addAll(services.stream().map(s -> new Service(this, s)).collect(toSet()));
        }
    }
}

@Entity
@Table(uniqueConstraints = @UniqueConstraint(name = "UQ_lic_service", columnNames = { "license_id", "service" }))
public class Service {

    // ...

    @ManyToOne(cascade = CascadeType.ALL)
    @JoinColumn(name = "license_id", nullable = false)
    private License license;

    @Column(nullable = false, length = 255)
    private String service;

    protected Service(License license, String service) {
        this.license = license;
        this.service = service;
    }
}

```

Now I need to update the `License` like:

```
    License license = getSomeExistingLicenseWithServices(...);
    // The existing license has two services "firstService", "secondService"
    HashSet<String> services = new HashSet<>();
    services.add("firstService");
    license.setServices(services);
    licenseRepository.save(license); // A spring-data-jpa-repository

```

Running this, I get the following exception:

```
Caused by: org.h2.jdbc.JdbcSQLException: Eindeutiger Index oder Primärschlüssel verletzt: "UQ_LIC_SERVICE_INDEX_8 ON PUBLIC.SERVICE(LICENSE_ID, SERVICE) VALUES (1, 'firstService', 1)"
Unique index or primary key violation: "UQ_LIC_SERVICE_INDEX_8 ON PUBLIC.SERVICE(LICENSE_ID, SERVICE) VALUES (1, 'firstService', 1)"; SQL statement:
insert into service (id, lock_no, license_id, service) values (null, ?, ?, ?) [23505-196]

```

I expected all 'old' (='orphaned') `Service`s to become deleted, when I call `setServices` with a new `HashSet`. What I am doing wrong? TIA!