How the compiler understands your Java class

I have the following static factory method that creates a list view out of an int array:

	public class ListFactory {
	public static List<Integer> newInstance(final int[] numbers) {
	return new AbstractList<Integer>() {
	@Override
	public Integer get(int index) {
	return numbers[index];
	}
	@Override
	public int size() {
	return numbers.length;
	}
	};
	}
	}

view raw ListFactory.java hosted with ❤ by GitHub

In "Effective Java", Joshua Bloch mentioned this as an

Adapter that allows an int array to be viewed as a list of Integer instances

However, I remember that Adapter pattern uses composition and the instance of the anonymous list implementation should therefore use the int[] as a member field. To verify the hypothesis and understand how the class is understood by the compiler, one can use the following command:

javac -d . -XD-printflat ListFactory.java

From the output, one can clearly understand how the final parameter is passed to the inner anonymous class implementation:

	public class ListFactory {
	public ListFactory() {
	super();
	}
	public static List newInstance(final int[] numbers) {
	return new ListFactory$1(numbers);
	}
	}
	class ListFactory$1 extends AbstractList {
	/*synthetic*/ final int[] val$numbers;
	ListFactory$1(/*synthetic*/ final int[] val$numbers) {
	this.val$numbers = val$numbers;
	super();
	}
	@Override()
	public Integer get(int index) {
	return Integer.valueOf(val$numbers[index]);
	}
	@Override()
	public int size() {
	return val$numbers.length;
	}
	@Override()
	/*synthetic*/ public Object get(/*synthetic*/ int index) {
	return this.get(index);
	}
	}

view raw ListFactory.java hosted with ❤ by GitHub