What is the likely issue when this program executes?

public class SharedResource {
    private final int[] data = new int[10];

    public synchronized void modifyData() {
        for (int i = 0; i < data.length; i++) {
            data[i] = data[i] + 1;
        }
    }
    
      public void printData() {
        for (int i = 0; i < data.length; i++) {
            System.out.print(data[i] + " ");
        }
    }
    
    public static void main(String[] args) {
        SharedResource sr = new SharedResource();
        Thread t1 = new Thread(() -> sr.modifyData());
        Thread t2 = new Thread(() -> sr.modifyData());
        t1.start();
        t2.start();
        sr.printData();
    }
}