The relationship between classes and classes in Java

1. generalization (generalization)

As I understand, generalization is the way that subclasses inherit the parent class, and they can extend their capabilities

Eg:extend Implements

2. dependence (Dependency)

For two relatively independent objects, when one object is responsible for constructing an instance of another object, or a service that relies on another object, the two objects are primarily dependent.

As: local variables, parameters of methods, or calls to static methods

Eg: you need a boat to cross the river.

3. Association (Association)

When object A is added to object B and becomes part of Object B, the aggregation relationship is between object B and object A. Aggregation is one kind of correlation relation, it is strong association relation, emphasizing the relation between whole and part .

4. Synthesis (composition)

1, the synthesis relation is one kind of correlation relation, is also stronger than the aggregation relation.
2, it requires the ordinary aggregation relationship represents the whole object is responsible for representing the part of the object's life cycle.

The relationship between classes and classes in Java