Source code analysis of ArrayList

ArrayList The source code parsing

1.1 Underlying data structure

Definition ： Realization List Scalable array implementation of interface .

Array characteristics ：

• Quick query ： Arrays open up continuous space , Therefore, you can rely on the index for fast query .
• Add or delete slowly ： Every time you delete an element , You need to change the length of the array 、 Copy and move element locations .

1.2 Inheritance relationships

1.2.1Serializable Interface

Serialization of classes is implemented by java.io.Serializable Interface class enable . Classes that do not implement this interface will not serialize or deserialize any state . All subtypes of a serializable class are serializable . The serialization interface has no methods or fields , Only used to identify serializable semantics .

java.io.Serializable The interface is a Marker type Interface , There are no methods and fields .

1.8 Source code comments

If a serializable class does not explicitly declare a serialVersionUID, then the serialization runtime will calculate a default serialVersionUID value for that class based on various aspects of the class, as described in the Java Object Serialization Specification. However, it is strongly recommended that all serializable classes explic