java - static initialization block

Foo.java

/*

original question: https://twitter.com/SchwarzeLocke/status/574632128270442497

How could I achieve this #scala code easily in #java?
> val a = Set("a", "b")
> val b = Set("c", "d")
> val c = (a ++ b + "x" + "y").toArray

Many thanks to @Szernex and @Waldteufel

*/
class Foo {
	public static final List<String> a = Arrays.asList("a", "b");
	public static final List<String> b = Arrays.asList("c", "d");

	private static final List<String> tmp;
	public static final String[] c;
	
	static {
		tmp = new LinkedList<String>();

		tmp.addAll(a);
		tmp.addAll(b);

		tmp.add("x");
		tmp.add("y");
		
		c = tmp.toArray(new String[tmp.size()]);
	};
}