# Java源码分析之Vector

**Repository Path**: fpfgitmy_admin/java-source-code-vector

## Basic Information

- **Project Name**: Java源码分析之Vector
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 1
- **Forks**: 0
- **Created**: 2021-04-28
- **Last Updated**: 2021-04-28

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

#### Vector源码分析
+ jdk7和jdk8不变
+ 与Arraylist扩容方式不同
+ 原始长度为10，代码如下
```
    public Vector() {
        this(10);
    }
```
+ 扩容为2倍，代码如下
```
    private void grow(int minCapacity) {
        // overflow-conscious code
        int oldCapacity = elementData.length;
        int newCapacity = oldCapacity + ((capacityIncrement > 0) ?
                                         capacityIncrement : oldCapacity);
        if (newCapacity - minCapacity < 0)
            newCapacity = minCapacity;
        if (newCapacity - MAX_ARRAY_SIZE > 0)
            newCapacity = hugeCapacity(minCapacity);
        elementData = Arrays.copyOf(elementData, newCapacity);
    }
```
+ 线程同步
```
    public synchronized boolean add(E e) {
        modCount++;
        ensureCapacityHelper(elementCount + 1);
        elementData[elementCount++] = e;
        return true;
    }
```
+ 古老的方法，不推荐使用，如果非要使用线程安全的集合，则可以使用`Collections.synchronizedList()
`使其线程安全