java se 8 rules for implementing abstract methods from extended interfaces

Question

why does this code compile printing "Class 2" (java se8; eclipse) even if abstract method is NOT implemented in first concrete class?

IDE gives me the hint: The type Class1 must implement the inherited abstract method Interface1.method1()

package uebungen.u025;



interface Interface1 {
        public void method1();
    }

    interface Interface2 extends Interface1 {// line n1
        public void method2();
    }

    class Class1 implements Interface2 {// line n2
        @Override
        public void method2() {
            System.out.println("Class 1");
        }
    }

        class Class2 extends Class1 {// line n3
            @Override
            public void method2() {
                System.out.println("Class 2");
            }

        }

        public class Test {
            public static void main(String[] args) {

                Class1 x = new Class2();
                x.method2();
            }
        }