Say I have at least two entities. 
    @Entity
    public class Process {
    
        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        private Long id;
    
        @Column(unique = true)
        private String name;
    
        @ManyToAny(
                metaColumn = @Column(name = "node_type"),
                fetch = FetchType.LAZY
        )
        @AnyMetaDef(
                idType = "long", metaType = "string",
                metaValues = {
                        @MetaValue(targetEntity = Milestone.class, value = MILESTONE_DISC),
                        @MetaValue(targetEntity = Phase.class, value = PHASE_DISC)
                }
        )
        @Cascade({org.hibernate.annotations.CascadeType.ALL})
        @JoinTable(
                name = "process_nodes",
                joinColumns = @JoinColumn(name = "process_id", nullable = false),
                inverseJoinColumns = @JoinColumn(name = "node_id", nullable = false)
        )
        private Collection<ProcessNode> nodes = new ArrayList<>();
    
        ...
    }
-------
    @Entity
    @ToString
    @DiscriminatorValue(MILESTONE_DISC)
    public class Milestone implements ProcessNode {
    
    
        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        private Long id;
    
        private String name;
    
        @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
        private Collection<ResultDefinition> results;
    
        @ToString.Exclude
        @ManyToOne(fetch = FetchType.LAZY)
        @Transient
        private Process process;
    
    ...
    }
Now I want to use spring data jpa specification to find (all) processes which have a milestone with name "S5".
Note that Milestone is a ProcessNode and there is another Entity called Phase which is also a ProcessNode. These can be contained in the "nodes" collection of my Process Entity.
I tried to write something like this:
        public static Specification<Process> hasMilestoneWithName(final String milestoneName) {
        return (Specification<Process>) (root, query, criteriaBuilder) -> {
            Path<?> namePath = root.join("nodes").get("name");
            return criteriaBuilder.equal(namePath, milestoneName);
        };
    }
This does not work, but throws:
> Caused by: java.lang.IllegalArgumentException: Unable to locate Attribute with the the given name [nodes] on this ManagedType [com.smatrics.dffs.processservice.model.entities.Process]
I don't really know how to use the API. Examples often refer to a meta-model that would be generated by the IDE or maven, but I really do not want to have any static generated resources. Please help me resolve this with Specification of spring-data-jpa without a generated meta-model.
Also if you could help me write the hql it would be awesome.
Thanks!

select *
from process
where id in (
select process_id
from milestone
where name = 'S5'
)