Product Version = NetBeans IDE 7.4 Beta (Build 201307092200)
Operating System = Windows 8 version 6.2 running on x86
Java; VM; Vendor = 1.8.0-ea
Runtime = Java HotSpot(TM) Client VM 25.0-b41

Consider this interface:
interface ConvertLambda {
	void foo();
	
	static void bar() {
		ConvertLambda cl = () -> System.out.println("foo()");
	}
}

NetBeans shows two hints for converting the lambda.

First hint is: "Use block as the lambda's body" ("Convert lambda body to use a block rather than an expression")
Resulting in this code:
static void bar() {
	ConvertLambda cl = () -> {
		return System.out.println("foo()");
	};
}

Apparently, the "return" is wrong here.

Second hint is: "Convert lambda expression to anonymous innerclass"
Resulting in this code:
static void bar() {
	ConvertLambda cl = new ConvertLambda() {

		public void foo() {
			return System.out.println("foo()");
		}
	};
}

Again, the "return" is wrong.