Complex initializations need only be done once and the result stored for later use. For example if you need to create a list of integer values and then load them, you can create a class that stores the information and then load it as follows. Be sure that the resource file needs to stored in the same location as the class file or the classloader will fail:
class someClass { private static final int[] values = initsomeClass(); private static final int countVALUES = 27; private static int[] initsomeClass() { int[] values = new int[countVALUES]; try { DataInputStream data = newDataInputStream(someClass.class.getResourceAsStream("someClass.dat")); for (int i = 0; i < countVALUES; ++i) p[i] = data.readInt(); data.close(); } catch (IOException e) { return null; } return values