Noob failed to render a triangle on screen

[Potty_Jr]

Hi guys, I'm new to OpenGL & lwjgl. Today I was following the tutorial for lwjgl 3 on https://ahbejarano.gitbook.io/lwjglgamedev and trying to render a triangle in my window like in chapter 3, but even thought I copied the code given by the author, what I got was a blank window. I'm using Java 8 and the author is using a higher version, he used the record keyword in ShaderProgram which I replaced with an inner class, the rest should be exactly the same. My code is in the attachment, could anyone help?