stevenschwenke

    private int methodWithoutParameter() {
        return 0;
    }

    /**
     * Equals exactly method signature of java.util.function.Function:apply
     */
    private int methodWithParameter(int x) {
        return x;
    }

stevenschwenke

@FunctionalInterface
public interface SimpleFunctionalInterface {
    public int returnAnswerToUltimateQuestion();
}

    @Test
    public void normalInterfaceOnlyOneAbstractMethod() {

        int x = 1;