Need help starting a security system

Hi everyone I am Ace and I just joined this great forum.

I am originally from Computer Science background but electronics and its practicality of things is seriously gaining its control over me.

So I've been meaning to make a security system for a long time but I have no knowledge as to how to proceed about it.

What I want to make is a fancy (layman terms since I am a CS student) security key system in which a user enters his password and the door unlocks.

It will be a door lock system. All I know that it should have a decent display saying whether the user is accepted or not, a keypad terminal, a microprocessor, a motor to lock and unlock to rod which goes in ensure lock (this is flexible since its the hardware)

What I don't know is - which microprocessor should I use to do this? I don't know how to attach a display to a microprocessor to get things done? I don't even know if I should use a microprocessor at all?

Basically, if you were to teach your kid the simple and basic electronics as to how to build a good security system like that just for fun sake, that's the way I think you should teach me to understand for this.

Plus, I also wanted to know - How can I implement Java in microprocessors? I mean, are there are microprocessor where JVM comes pre - installed(see, I know this sounds stupid!)?

Please, all this curiosity is killing me..

Build AVR Project with Java
https://www.circuitlake.com/build-avr-project-with-java.html

After reading the above post, I've learned that
1. ATmega8 is a micro-controller. What I did not understand: A microprocessor is a single object, whereas a micro-controller comes with other chips combined on a PCB?
2. AVR is a assembly language. What I did not understand: For which microprocessor/controller is this AVR assembly language for? Is it for everyone or for some limited controllers?

3.

The NanoVM for Asuro replaces the original firmware of the Asuro with a Java virtual machine capable of running a subset of the virtual machine command set.

Click to expand...

This means that the controller originally came with a firmware. So, where do I buy this controller with I want to buy with the JVM installed?

Questions

1. Don't controllers come with JVM pre-installed?
2. If they do, what are these controllers then called? Like do they have special names or something?
3. If the controllers don't have JVM, what do they have?
4. What if I were to do all of this in C or C++? Not that I have anything against Java, on the contrary, I love Java

Check out Cool components. There you will find ready built micro based boards to get you started with stuff like touch screen displays.

**broken link removed**