Again, This question is derive for K&B Book from Chapter7: Generics and Collections in the Self Test section: 9.Given a properly prepared String array containing five elements, which range of results could a proper invocation of Arrays.binarySearch() produce? ... E. -5 through 4 F. -5 through 5 G. -6 through 4 ... The answer is G. Why not answers E. Because the insertion point is -(Insertion point) -1. This string array has five elements so max index is 4 and the min insertion point should be -4 -1 = -5. I don't understand, why this array min insertion point is -6

Negative value indicates unsuccessful search and [-(Insertion point) -1 ]specifies where to insert the element.

The array already contains elements in positions 0,1,2,3 and 4. So we can insert elements from 5 onwards. So the answer should be G itself since -(-6)-1 = 5.

If the max search index is 4 that means there are 5 object in the collection.Lets name then A-E for then the insertion points will be 6(5 before each elements and 1 at the end). search index: [0 1 2 3 4 ] | A | B | C | D | E insertion points [-1 -2 -3 -4 -5 -6(end)] [ January 09, 2007: Message edited by: Sanjeev Kumar Singh ]

~Sanjeev Singh<br />SCJP 1.5

Tanakorn Numrubporn
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Thank you again for knowledgh that I gain. But which of the two above replies is correct assume about the insertion point; between the first position that we can insert in array OR the space between adjacency elements of the array.