Java array pass without reference

Question

I am trying to pass an array without using a reference, but directly with the values :

    public static void main(String[] args){
            int[] result = insertionSort({10,3,4,12,2});
    }

    public static int[] insertionSort(int[] arr){
        return arr;
    }

but it returns the following exception :

Exception in thread "main" java.lang.Error: Unresolved compilation problems: 
Syntax error on token(s), misplaced construct(s)
Syntax error on token ")", delete this token

When I try the following code , it works , can anybody please explain the reason ?

    public static void main(String[] args){
        int[] arr = {10,3,4,12,2};
        int[] result = insertionSort(arr);  
    }

    public static int[] insertionSort(int[] arr){
        return arr;
    }

Answer 1

It has to be

int[] result = insertionSort(new int[]{10,3,4,12,2});

{10,3,4,12,2} is a syntactic sugar for array initialization, which must go with the declaration statement like the one in the following -

int[] arr = {10,3,4,12,2};

Something as follows is not allowed too -

int[] arr; // already declared here but not initialized yet
arr = {10,3,4,12,2}; // not a declaration statement so not allowed

Answer 2

insertionSort({10,3,4,12,2})

is not valid java because you don't specify a type in your method call. The JVM does not know what type of array this is. Is it an array with double values or with int values?

What you can do is insertionSort(new int[]{10, 3 ,4 12, 2});