protected static int[] concat(@Nullable int[] arr,int... obj){
  int[] newArr;
  if (arr == null || arr.length == 0)   newArr=obj;
 else {
    newArr=Arrays.copyOf(arr,arr.length + obj.length);
    System.arraycopy(obj,0,newArr,arr.length,obj.length);
  }
  return newArr;
}

protected static int [ ] concat ( @ Nullable int [ ] arr , int ... obj ) { int [ ] newArr ; if ( arr == null || arr . length == 0 ) newArr = obj ; else { newArr = Arrays . copyOf ( arr , arr . length + obj . length ) ; System . arraycopy ( obj , 0 , newArr , arr . length , obj . length ) ; } return newArr ; }
concatenates elements to an int array .
