ArrayList VS Vector In Java: In this article, we will discuss the difference between ArrayList Vs Vector classes in detail. Lets us move on and discuss the key differences between these 2 List classes
ArrayList VS Vector
| ArrayList | Vector |
| It is introduced in the original collection framework in Java 1.2 version | It is a legacy class including Stack, Dictionary, HashTable & Properties and introduced in Java 1.0 version |
| ArrayList methods are non-synchronized | All legacy collection classes are synchronized, thus Vector is synchronized (i.e.; all methods are synchronized) |
| As ArrayList is non-synchronized, hence it isn’t thread-safe. So, the programmer needs to handle thread-safety while working in a multi-threaded environment | As Vector is synchronized, hence it is thread-safe. So, no need to worry while working in a multi-threaded environment, as only one thread gets a chance to work at any given time |
| This is comparatively faster as it is non-synchronized, as threads don’t require to obtain the lock before operating on ArrayList | Performance-wise it is slower compared with ArrayList due to synchronization, as threads need to wait for their chance to operate on a Vector object |
| ArrayList increases its size by 50% of a current array when its capacity exceeds | It increases its size by 100% of a current array when its capacity exceeds |
| The only Iterator is allowed to iterate item/elements inside ArrayList | Both Iterator & Enumeration can be used to iterate item/elements inside Vector |
| ArrayList can be converted into synchronized ArrayList using static utility methods of Collections class collection.synchronizedList(ArrayList); | No need to do that, as already it is synchronized by default |
When to use ArrayList?
- If performance is the factor while storing element/objects, then ArrayList is apt
- But definitely, extra precautions need to be taken while working with a multiple-threaded environment
- Also, check how much extra space is required when List is full; if 50% of original size if required then ArrayList will fit the case perfectly
When to use Vector?
- If we aren’t concerned with performance, but element/objects need to be accessed in a thread-safe manner, then the Vector is the good choice
- But performance will be a big hit, as every thread to need to wait to obtain the lock before accessing vector element/objects
- Here, size increase in 2 times the original size; so if there are the number of items to be added then Vector will fit the bill perfectly
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