[U] list: vector

Author: c-rainstorm

java/source-code/jdk/collection/list-vector.md

@@ -0,0 +1,26 @@
+# Vector
+
+## 数组容量自增
+
+```java
+private void grow(int minCapacity) {
+    // overflow-conscious code
+    int oldCapacity = elementData.length;
+    // 默认容量翻倍
+    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);
+}
+```
+
+和 `ArrayList` 的区别是默认增长策略直接翻倍，且是同步的
+
+## 最后
+
+fast-fail。线程安全。
+
+没啥好说的。