Difference between ArrayList and Vector in Java

Main Difference

ArrayList is non-synchronized which implies various strings can take a shot at ArrayList in the meantime. For e.g. in the event that one string is performing an include operation ArrayList, there can be another string performing expel operation on ArrayList in the meantime in a multithreaded domain while Vector is synchronized. This implies on the off chance that one string is taking a shot at Vector, no other string can get a grip on it. Not at all like ArrayList as the only one string can perform an operation on a vector at once. Both ArrayList and Vector can develop and contract powerfully to keep up the ideal utilization of capacity, however, the way they resized is distinctive. ArrayList develops by half of its size when resized while Vector copies the span of itself, of course, when develops. ArrayList gives better execution as it is non-synchronized. Vector operations give poor execution as they are string safe, the string which takes a shot at Vector gets a lock on it which makes other string hold up till the lock is discharged. Initially, let me clarify what is fall flat quick: If the accumulation (ArrayList, vector and so forth.) gets fundamentally changed by any methods, with the exception of from include or expel techniques for iterator, after production of iterator then the iterator will toss ConcurrentModificationException. Basic alteration alludes to the expansion or cancellation of components from the gathering. According to the Vector Javadoc, the Enumeration returned by Vector is not come up short quick. On the other side, the iterator and listIterator returned by ArrayList are come up short quick. The vector was not the piece of accumulation system, it has been incorporated into accumulations later. It can be considered as Legacy code. There is nothing about Vector which List gathering can’t do. In this way, Vector ought to be maintained a strategic distance from. On the off chance that there is a need of string safe operation make ArrayList synchronized as talked about in the following segment of this post or utilize CopyOnWriteArrayList which is a string safe variation of ArrayList. It altogether depends on upon the essential. If there is a need to perform “string safe” operation the vector is your most coherent choice as it promises that emerge string get to the collection without a moment’s delay. Synchronized operations eat up extra time stood out from non-synchronized ones so if there is no prerequisite for string safe operation, ArrayList is an unrivaled choice as execution will be upgraded by virtue of the concurrent strategies.


An ArrayList stores a variable number of things. This resemble making an assortment of articles, however with an ArrayList, things can be easily included and removed from the ArrayList and it is resized effectively. This can be incredibly useful, yet it’s slower than making an assortment of articles while using various segments. Note that for resizable courses of action of entire numbers, floats, and Strings, the users are able to use the Processing classes IntList, FloatList, and StringList. An ArrayList is a resizable-bunch execution of the Java List interface. It has various systems used to control and request its substance. Case in point, the length of the ArrayList is returned by its size () system, which is an entire number quality for the total number of parts in the summary. A segment is added to an ArrayList incorporate () method and is eradicated with empty () procedure. The get () system gives back the segment at the foreordained position in the once-over.


The Vector class realizes develop a capable bunch of articles. Like a group, it contains parts that can be gotten to using an entire number record. In any case, the range of a Vector can create or contract not surprisingly to suit including and emptying things after the Vector has been made. Each vector tries to propel stockpiling organization by keeping up a point of confinement and a capacityIncrement. The breaking point is constantly on any occasion as colossal as the vector size; it is ordinarily greater in light of the fact that as parts are added to the vector, the vector’s stockpiling augmentations in protuberances the measure of capacityIncrement. The iterators returned by this present class’ iterator and listIterator procedures are fall level speedy: if the vector is fundamentally changed at whatever point after the iterator is made, in any way except for through the iterator’s own remove or incorporate methods, the iterator will hurl a ConcurrentModificationException. Along these lines, even with synchronous conformity, the iterator misses the mark quickly and conveniently, rather than betting subjective, non-deterministic behavior at an undetermined time later on. The Enumerations returned by the segments system are not miss the mark brisk. As of the Java 2 phase v1.2, this class was retrofitted to realize the List interface, making it a person from the Java Collections Framework. Not in any manner like the new assembling executions, is Vector that can be synchronized. If a string safe execution is not required, it is endorsed to use ArrayList set up of Vector.

Key Differences

  • Only the vector can be synchronized from them two.
  • The legacy class from them two is a vector.
  • The execution of the ArrayList is quick when contrasted with the vector.

Video Explanation

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