Java: Creating Reference Type from Abstract class and interface

I am new to Java and I have read threads (here) that it is not possible to instantiate an abstract class. So, I tested it out.

The first test I did is shown below. And it seems like I can actually instantiate an abstract class and in fact, I actually have a new type which refers to the abstract class and the type is actually shared by all subclasses the extends it. This also means polymorhpism applies.

import java.util.*;

abstract class AbstractClass{
    public abstract void printname();
}


class Test1 extends AbstractClass{

    private String name;

    public Test1(String name){
        this.name = name;
    }

    public void printname(){
        System.out.println("My name is " + name);
    }
}

class Test2 extends AbstractClass{
        private String saysomething;

    public Test2(String saysomething){
        this.saysomething = saysomething;
    }

    public void printname(){
        System.out.println(saysomething);
    }
}

class TestingApp{
    public static void main(String[] args){
        AbstractClass[] abstractclass_list = {new Test1("JEFFFFFF") , new Test2("Hey , say something")};
        for(AbstractClass item : abstractclass_list){
            item.printname();
        }
    }
}

Then I did another test but this time, instead of working on abstract class, I decided to create a type which refers to Interface. It seems like I can instantiate an interface as well. I can actually create a type that refers to the interface. This type is shared by all the classes that implements this interface. And polymorphism applies again.

import java.util.*;

interface  AbstractInterface{
    public void printname();
}


class Test4 implements AbstractInterface{

    private String name;

    public Test4(String name){
        this.name = name;
    }

    public void printname(){
        System.out.println("My name is " + name);
    }
}

class Test3 implements AbstractInterface{
    private String saysomething;

    public Test3(String saysomething){
        this.saysomething = saysomething;
    }

    public void printname(){
        System.out.println(saysomething);
    }
}

class TestingAbstractInterfaceApp{
    public static void main(String[] args){
        AbstractInterface[] abstract_list = {new Test4("Helen") , new Test3("Hey , say my name")};
        for(AbstractInterface item : abstract_list){
            item.printname();
        }
    }
}

Question:

I am sensing there is something wrong with what I am doing in my code. But I cannot quite explain how come the code still works when theoretically, it is impossible to instantiate an abstract class and interface. Am I actually instantiating an abstract class and an interface in the examples shown above ? Because this seems like exactly what I have done, as I have a new type for the abstract class and interface. Please correct me, if my logic is wrong or if I am using the wrong words.

Update: SO I guess my misunderstanding is about type. I always thought type can only refer to normal Java classes but not abstract classes and interfaces. How does "type" actually work? Is it creating a reference?