class P
    {
    public static  void m1()
    {
    System.out.println("Parent");
    }
}
    class C extends P
    {
    public static void m1()
    {
    System.out.println("Child");
    }
}
class Test{
    public static void main(String args[])
    {
    Parent p=new Parent();//Parent
    Child c=new Child();  //Child
    Parent p=new Child();  //Parent
    }
    }

If the both parent and child class method are static the compiler is responsible for method resolution based on reference type

class Parent
{
public void m1()
{
System.out.println("Parent");
}}
class Child extends Parent
{
public void m1()
{
System.out.println("Child")
}
}
class Test
{
public static void main(String args[])
{
Parent p=new Parent(); //Parent 
Child c=new Child();   //Child
Parent p=new Child();  //Child
}
}

If both method are not static  jvm is responsible for method resolution based on run time object