Java - Creating random numbers with no duplicate

I need to create random numbers that will run through an array without duplicates.

The problem is the duplication and I can't use any of the utils except the Scanner for input like java.util.Random or java.util.ArrayList.

I use a function called random and the function newNum is where I need what I have asked.

The problam is it's printing duplicate numbers and giving me an error after the eighth or ninth print.

package exercise;

import java.util.Scanner;

public class Bingo {

static int size = 10;
static int num;
static int[] arr = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
private static Scanner sc;

public static void main(String[] args) {

    System.out.print("Press Enter to start: ");
    sc = new Scanner(System.in);
    System.out.println("");

    int num = random();

    while (size > 0) {

        String input = sc.nextLine();

        if (input.isEmpty()) {

            System.out.println(num);
            size--;
            newArray(num);
            num = random();
            newNum(num);

        } else {
            System.out.println("Input was enterd!");
            break;
        }

    }

    System.out.println("End of program");

}

public static int random() {

    int max = 10;
    double r = Math.random();
    int num = (int) (r * max + 1);

    return num;
}

public static int newNum(int num) {

    int i = 0;
    while (num != arr[1]) {
        if (i <= num) {
            i++;
        } else {
            num = random();
        }
    }

    return num;
}

public static int newArray(int num) {

    int[] tempArray = arr;

    arr = new int[size];

    int x = num - 1;
    for (int i = 0; i < x; i++) {
        if (i < size) {
            arr[i] = tempArray[i];
        }
    }
    for (int i = num; i < size; i++) {
        if (i < size) {
            int y = i - 1;
            arr[y] = tempArray[i];
        } else {
            int a = size - 1;
            arr[a] = tempArray[size];
        }
    }
    return num;
}

}