Java Vector Data Structure Explained

In Java, the underlying data structure of the Vector class is an object array (Object[]). This means that Vector can store objects of any type.

Vector is a type of dynamic array that can automatically expand and shrink as needed. When the number of elements in a Vector exceeds its current capacity, it creates a larger array and copies the existing elements to the new array. This process is known as resizing. Similarly, when elements are removed from a Vector and its size becomes significantly smaller than its capacity, the Vector will shrink to an appropriate size to save memory.

Since Vector’s underlying implementation uses arrays, accessing elements in Vector is very efficient as elements can be accessed directly by index. However, inserting and deleting elements may involve moving the array, making it relatively slower, especially for large Vectors.

It is important to note that Java 1.2 introduced a more flexible and efficient ArrayList class, which is the preferred alternative to Vector in most cases unless thread safety is needed. Vector’s methods are synchronized, making it suitable for use in multi-threaded environments to ensure thread safety, but ArrayList is more commonly used in single-threaded environments.