Java technology combing ArrayList


Java technology combing – ArrayList combing ArrayList from source code and actual combat



1、 Principle

2、 Parameters

 * Default initial capacity.
private static final int DEFAULT_CAPACITY = 10;

Default size

     * Shared empty array instance used for empty instances.
    private static final Object[] EMPTY_ELEMENTDATA = {};
     * Shared empty array instance used for default sized empty instances. We
     * distinguish this from EMPTY_ELEMENTDATA to know how much to inflate when
     * first element is added.
    private static final Object[] DEFAULTCAPACITY_EMPTY_ELEMENTDATA = {};
     * The array buffer into which the elements of the ArrayList are stored.
     * The capacity of the ArrayList is the length of this array buffer. Any
     * empty ArrayList with elementData == DEFAULTCAPACITY_EMPTY_ELEMENTDATA
     * will be expanded to DEFAULT_CAPACITY when the first element is added.
    transient Object[] elementData; // non-private to simplify nested class access
 * The size of the ArrayList (the number of elements it contains).
 * @serial
private int size;

3、 Constructor

There are three kinds

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