Can we use @ManyToOne annotation in isolation ?

 you can use the `@ManyToOne` annotation in isolation. This annotation is used to define a many-to-one relationship between two entities in a Java Persistence API (JPA) context. 

For example, in your `Product` entity, you have a many-to-one relationship with the `Category` entity. This means that many products can belong to one category. 

Here's a simplified example:

@Entity

public class Product {

    @ManyToOne

    @JoinColumn(name = "category_id", nullable = false)

    private Category category;

In this case, the `@ManyToOne` annotation is used to indicate that many instances of `Product` can be associated with one instance of `Category`. The `@JoinColumn` annotation is used to specify the column that is used for joining an entity association or element collection.

However, it's important to note that while you can use `@ManyToOne` without `@OneToMany`, doing so means you won't be able to navigate the relationship from `Category` to `Product`. If you need to get all products for a specific category, you would need to add a `@OneToMany` annotation in your `Category` entity.