What steps should be taken to turn a class into a full-fledged entity in the system?

To turn a class into a full-fledged entity in a Java system, you need to perform several steps:

1. Define the class with fields and methods — describe the properties and behavior of the object.
2. Create constructors for initializing objects.
3. Implement access methods (getters and setters) to manage the object's state.
4. Override equals(), hashCode(), and toString() methods for proper comparison, hashing, and output of the object.
5. Encapsulate data — make fields private and control access through methods.
6. Implement interfaces or inheritance if necessary for integration with other parts of the system.

Example:

public class User {
    private String name;
    private int age;

    public User(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        User user = (User) o;
        return age == user.age && name.equals(user.name);
    }

    @Override
    public int hashCode() {
        return Objects.hash(name, age);
    }

    @Override
    public String toString() {
        return "User{name='" + name + "', age=" + age + '}';
    }
}

Thus, the class becomes a full-fledged entity that can be used in business logic and stored in collections, databases, etc.