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doubt in List.indexOf()

 
Greenhorn
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Hi ranchers
why are the two outputs in the following code -1(unfound). As you can see, there is 4 in the array and I created a list using Array.asList()
 
Ranch Hand
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here it is :


I think that when the JVM autoboxes int to Integer, the Integer.equals() method is ignored or something like that.
 
Author and all-around good cowpoke
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Looks like the indexOf is using identity of the reference, not the content of the object.

Bill
 
Fissehaye Kahsay
Greenhorn
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thanks for your help
but how can I get the index of 4 in the int[] not in Integer[] ?. I'm forced to use the int[] instead of Integer[] (just calling a method which takes int[])
 
Evan Caballero
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In fact, when you do i.asList(), it returns a list of int[] (List<int[]>) with one element :/

like [{ 1, 2, 3, 4, 5, 6, 7, 8, 9 }]

so, there is no element at index 4 ; there is only an element at index 0, which is your original int[].

the asList method considers that you want to build a list from one int[], which IS an object. It is like if you were doing Arrays.asList(i1, i2, i3, i4), where i1 i2 i3 and i4 are int[] objects.
 
Sheriff
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Evan is right. Arrays.asList will only work on objects, not on primitives. You will need to box the entire array - convert each element into Integer objects first. You may want to switch to a "regular" List implementation:
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