Java Hold Object Learning notes

1. Holding object: The container, the object that holds the other object;

2. Interator can remove the last object produced by Next (), which means that next () must be called before a remove () is called.

3. Iterators unify the way the container is accessed;

4. Programs usually create new objects based on certain conditions that are known to the runtime;

5. Any number of objects need to be created at any time and at any location;

6. List Set Queue map,collection Container;

7. By using generics, you can prevent the compiler from placing an object of the wrong type in a container, such as arraylist<apple>;

8. If you do not need to use the index of each object, you can use the foreach syntax to select each element in the list;

9. Collection:list Set Queue

Map:arraylist Map

list<apple> apples = new arraylist<apple> (), creates an object of a specific class, converts its type to its corresponding interface, and then uses the interface in the rest of the code;

The behavior of List has changed according to the behavior of equal ().

Remove in list note that the automatic packing mechanism is used in a timely manner;

13.

list<integer> sub = pt.sublist (0, 3);
System.out.println (Sub.add (12));

There is a problem with this usage;

Next is to take itself and move one bit later, previous is to move forward one and then take a value.

Java Hold Object Learning notes