Caused by: org.hibernate.HibernateException: Missing table: con_cat
   at org.hibernate.cfg.Configuration.validateSchema(Configuration.java:1086)
   at org.hibernate.tool.hbm2ddl.SchemaValidator.validate(SchemaValidator.java:116)
   at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:317)...

..........@ManyToMany(cascade={CascadeType.PERSIST, CascadeType.MERGE},
               mappedBy = "consumers",
               targetEntity = Category.class)
          
    private List<Category> categories = new ArrayList();
   
    public Category getCategories() {
       if (this.categories.isEmpty()) {
           return null;
       }
       return this.categories.get(0);
       }
   
    public void setCategory(Category category) {
       if (this.categories.isEmpty()) {
           this.categories.add(category);
       } else {
           this.categories.set(1, category);
       }

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id")
    private Long id;
 
    private int con_id;  // consumer ID - this id is for App use
     .....
    // getter. setters
..........

.....    @ManyToMany(targetEntity=Consumer.class, cascade={CascadeType.PERSIST, CascadeType.MERGE})
    @JoinTable(
        name="con_cat",
        joinColumns=@JoinColumn(name="cat_id", referencedColumnName="cat_id"),
        inverseJoinColumns=@JoinColumn(name="con_id", referencedColumnName="con_id")
    )
    private List<Consumer> consumers = new ArrayList();
   
    public Consumer getConsumers() {
       if (this.consumers.isEmpty()) {
           return null;
       }
       return this.consumers.get(0);
       }
   
    public void setConsumer(Consumer consumer) {
       if (this.consumers.isEmpty()) {
           this.consumers.add(consumer);
       } else {
           this.consumers.set(1, consumer);
     }
     
    @Id   
    @GeneratedValue(strategy=GenerationType.AUTO)           
    @Column(name = "id")   
    private Long id; 

    private int cat_id;   // category ID,  also for App use
  // getters & setters ...