Java int vs Integer Example

gistfile1.java

ArrayList<Integer> someNumbers= new ArrayList<Integer>();
ArrayList<int> luckyNumbers= new ArrayList<int>();

//This will cause a compiletime error
//

JavaExample.java:23: unexpected type
found   : int
required: reference
        ArrayList<int> luckyNumbers= new ArrayList<int>();
                  ^
JavaExample.java:23: unexpected type
found   : int
required: reference
        ArrayList<int> luckyNumbers= new ArrayList<int>();
                                                   ^
2 errors