Demonstrates how to use lombok's @ExtensionMethod annotation on objects and primitive types.

ExtensionMethodTest.java

import lombok.ExtensionMethod;

@ExtensionMethod(Extensions.class)
public class ExtensionMethodTest {

	public static void main(final String... args) {
		System.out.println(args.isNull()); //-> false
		System.out.println(null.isNull()); //-> true

		int i = 0;
		System.out.println(i.isNull()); //-> false
		// NOTE: i.isNull() works because calling a method on a reference is valid
		// syntactically, even if Java does not natively support calling methods on
		// primitive types. Lombok will rewrite the statement before the compiler
		// performs sematic analysis on what type of a reference "i" is and whether
		// it is valid to invoke a method on it.
		//
		// NOTE: 0.isNull() will not work because it is a syntax error to invoke a
		// method on a numeric literal.
	}
}

class Extensions {
	public static boolean isNull(final String[] array) {
		return null == array;
	}
	public static boolean isNull(final int i) {
		return false;
	}
}

Very nice, though still not as nice as other languages :) (Specifically, having to annotate the class calling the extension methods, and not being able invoke methods on literals).