Static And Dynamic Binding In OOPS

I have a question regarding static binding and dynamic binding. Say for example we have below hierarchy,

class Animal
{
public void eat() {
System.out.println("Animal Eating");
}
}

[Code] .....

1) a.eat(); // Prints Animal eating ---> Static Binding 2) a.eat(); // Prints Dog eating ----> Dynamic Binding

Static Binding means,compiler will be able to decide which method to call based on class type of reference variable at compile time.That is compiler will check whether method is available or not in class.

Dynamic binding means,at runtime JVM will run the method implementaton,based on the object which reference variable is pointing.

So basically compiler will check class type of reference variable and at runtime JVM will check what type of object reference variable is pointing.

Here my my doubt is , in below both cases,that is

1) a.eat(); // Prints Animal eating ---> Static Binding
2) a1.eat(); // Prints Dog eating ----> Dynamic Binding

At compile time,compiler will check whether method is available or not in class. Since eat() method is available ,then in both cases it should be Static binding. or at run time if JVM decides which method implementation to call,then JVM will check which object the reference variable is pointing,then in above 2 cases also JVM will check in Animal object and Dog object for the method eat(). Since eat() method available then both should be dynamic binding.

I am getting doubt on what parameters/conditions we are deciding which is static binding and which is dynamic binding .

Will compiler will check the type of reference variable and also type of object at compile time and when it is ambiguous it leaves the decision to JVM?

Or is it like if method call and method implementation belong to same class then it is static binding and if method call and method implementation belong to different class in same inheritance hierarchy then dynamic binding.