Selection sorting an int array
Few points.

There is no need to create a object for SelectionSort. Declare it static. 

selectionSort(arr);

Your variable names should be made better. Its not recommended to use 'out' as variable, or int a[]. You can use int inputArr[] as thats more descriptive. Imagine someone is reading your code then if you make their life easy by making your code more descriptive then job is done faster.

You can create a seperate swap method. This will structure your code properly. You can reuse the swap method for other sorting methods too.

private void swap(int out, int min)
{
int temp = a[out];
a[out] = a[min];
a[min] = temp;
}