Just like in Java:
static {
}
What should I do?
Extend currently doesn't support static initializers - see https://bugs.eclipse.org/bugs/show_bug.cgi?id=429141.
One possible workaround is to create a field you don't care about just for the side-effects of the initializer:
static val I_AM_ONLY_FOR_SIDE_EFFECTS = {
// Code you'd want in your static initializer
return 0
}