Remove object from ArrayList with some Object property

Question

I am maintaining one ArrayList of objects. And my object structure is Id, name, some other details. I need to remove one the object with some id value say(10) a

Answer 1

It is not possible¹ to remove instances of an element from an ArrayList without iterating the list in some way². The ArrayList is an array under the hood, and you need to examine each element in the array to see whether it matches the criteria for removal. At the fundamental level, that entails a loop ... to iterate over the elements.

Also note that when you remove a single element from an array, all elements with positions after the removed elements need to be moved. On average, that will be half of the array elements.

Now, you can code these operations in ways that avoid you using an explicit for loop, but the iteration will be happening behind the scenes, no matter how you code it.

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^{1 - Not strictly true. Hypothetically, if you had a separate data structure that (for instance) mapped values to the indexes of elements in the ArrayList, then you could remove the elements without iterating. But I can't see how you could manage that data structure efficiently.}

^{2 - Iteration doesn't just mean using an Iterator. For loops, Stream, Collections.removeIf and other solutions all entail iterating the elements of the list under the hood.}