int [] a1 = new int[]{1,2,3};
int [] a2 = new int[4];
int[][] a3 = new int[2][3];
String [] a4 = new String[]{"a","b","c"}; 
                    
Object aObj1 = a1;   //IntObject
Object aObj2 = a4;
//Object[] aObj3 = a1; IntObject
Object[] aObj4 = a3;  //IntObject
Object[] aObj5 = a4;

Why can a4 assign values to object, and object arrays, but not int