How to check Missing and Repeated number in array

 A array size n have element 1-n but one element is missing and one element is repeated .
public class MissingAndRepeatedElement {
static void searchMissingAndRepeated(int []arr){
     for (int i = 0; i < arr.length; i++) {
        if (arr[Math.abs(arr[i])-1]>0) {
            arr[Math.abs(arr[i])-1]=-arr[Math.abs(arr[i])-1];
        }
        else {
            System.out.println("reapted="+Math.abs(arr[i-1]));
        }
     }
        for (int j = 0; j < arr.length; j++) {
            if (arr[j]>0) {
                System.out.println("Missing="+(j+1));
        }       
    }
 }   
public static void main(String[] args) {
    int arr[]={7, 3,4, 5, 5, 6, 2};
    searchMissingAndRepeated(arr);
}       
}