This simple snippet can cause javac (from the JDK 8) to crash : public class TestExtendConsumer { @FunctionalInterface public interface NumberConsumer< E extends Number> extends java.util.function.Consumer< E>{void accept(E number);} private static < E extends Number> void extend(E number) { System.out.println(number); } public static void main(String[] args) { NumberConsumer numberConsumer = TestExtendConsumer::extend; numberConsumer.accept(1); } } Impressive.… Read More »