A DESCRIPTION OF THE PROBLEM :
the doc for method Arrays.binarySearch() is wrong, which says the return value is the index of the search key when the key was found, otherwise -(insertion point - 1); but actually, the return value is - (insertion point + 1) when the key was not found!

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
(1)construct a array, like <code>int[] array = new int[]{1, 2, 3, 5}; </code>
(2)use the method Arrays.binarySearch(int[], int) to search the int value '4'
(3)use return value to resolve the insertion point


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import java.util.Arrays;

public class ArraysTest {

    public static void main(String[] args) {
        int[] array = new int[]{1,2,3,5};
        int target = 4;
        int retVal = Arrays.binarySearch(array, target);
        int insertionPoint = -retVal + 1;

        System.out.println(insertionPoint);
    }

}
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