which one is called? what is the output? why? what is the difference? (Q2 is more important for me)

Question

imagine these classes:

class Parent{
public void f(){
System.out.println("f() in Parent");
}
}
//--------------------------------------------------------------
class Child extends Parent{
public void f(){
System.out.println("f() in Child");
}
}
//--------------------------------------------------------------
public class SomeClass {
public void method(Parent p){
System.out.println("method(Parent)");
}
public void method(Child p){
System.out.println("method(Child)");
}
}
//--------------------------------------------------------------
Now I have 2 Questions:

Q1:
Parent obj1 = new Child();
obj1.f();

Q2:
SomeClass obj2 = new SomeClass();
Parent obj3 = new Child();
obj2.method(obj3);

Answer 1

q1: f() in Child() q2:metod(Parent). java checks types at compile time. obj3 defined as Parent. that is why compiler chooses method(Parent p). the difference is that in q1 type is checked at runtime.