start a window, listen for keyboard events and change color by clearing the color bit/buffer

build.gradle

plugins {
    id 'java'
}

repositories.mavenCentral()

dependencies {
    // for lwjgl demos
    implementation 'org.joml:joml:1.10.5'

    implementation "org.lwjgl:lwjgl:$lwjglVersion"
    implementation "org.lwjgl:lwjgl:$lwjglVersion:natives-linux"
    implementation "org.lwjgl:lwjgl-glfw:$lwjglVersion"
    implementation "org.lwjgl:lwjgl-glfw:$lwjglVersion:natives-linux"
    implementation "org.lwjgl:lwjgl-tinyfd:$lwjglVersion"
    implementation "org.lwjgl:lwjgl-tinyfd:$lwjglVersion:natives-linux"
    implementation "org.lwjgl:lwjgl-opengl:$lwjglVersion"
    implementation "org.lwjgl:lwjgl-opengl:$lwjglVersion:natives-linux"
}

OpenGlChangeColors.java

package com.youtube.ElegantWhelp.tutorial;

import lombok.RequiredArgsConstructor;
import org.lwjgl.glfw.GLFW;
import org.lwjgl.glfw.GLFWVidMode;
import org.lwjgl.opengl.GL;
import org.lwjgl.opengl.GL11C;

import javax.swing.*;
import java.awt.*;
import java.util.Objects;

@SuppressWarnings("CommentedOutCode")
public class OpenGlChangeColors {

    public static final Color LIGHT_BLUE = new Color(152, 152, 255);
    public static final Color LIGHT_PURPLE = new Color(190, 152, 255);
    public static final Color LIGHT_VIOLET = new Color(152, 86, 225);
    public static final Color LIGHT_MANGO = new Color(255, 174, 124);
    public static final Color LIGHT_RED = new Color(255, 124, 124);
    public static final Color LIGHT_GREEN = new Color(191, 255, 215);

    public static void main(String[] args) {
        GLFW.glfwInit();

        GLFWVidMode glfwVidMode = GLFW.glfwGetVideoMode(GLFW.glfwGetPrimaryMonitor());
        Objects.requireNonNull(glfwVidMode);
        
        String[] options = {"Windowed (small)", "Windowed (medium)", "Full Screen"};
        var selection = JOptionPane.showOptionDialog(
                null,
                "Select one:",
                "Resolution Selection",
                JOptionPane.YES_NO_OPTION,
                JOptionPane.QUESTION_MESSAGE,
                null,
                options,
                options[0]);

        long window = switch (selection) {
            case 0 -> GLFW.glfwCreateWindow(
                    glfwVidMode.width() / 3,
                    glfwVidMode.height() / 3,
                    "ok",
                    0,
                    0);
            case 1 -> GLFW.glfwCreateWindow(
                glfwVidMode.width() / 2,
                glfwVidMode.height() / 2,
                "ok",
                0,
                0);
            case 2 -> GLFW.glfwCreateWindow(
                glfwVidMode.width(),
                glfwVidMode.height(),
                "ok",
                GLFW.glfwGetPrimaryMonitor(),
                0);
            default -> throw new IllegalStateException("Unexpected value: " + selection);
        };

        if (selection != 2) GLFW.glfwSetWindowPos(window,
                glfwVidMode.width() / 10,
                glfwVidMode.height() / 5);

        GLFW.glfwShowWindow(window);
        GLFW.glfwMakeContextCurrent(window);
        GL.createCapabilities();
        
        /*
        GL11C.glClearColor(210.9f, .1f, 0.1f, 1f);
        GL11C.glClear(GL11C.GL_COLOR_BUFFER_BIT);
        GLFW.glfwSwapBuffers(window);
        */
        ColorManager colorManager = new ColorManager(window);
        colorManager.setColor(Color.LIGHT_GRAY);

        // noinspection resource
        GLFW.glfwSetKeyCallback(window, (long window1, int key, int scancode, int action, int mods) -> {
            if (colorManager.window == window1 && action == GLFW.GLFW_PRESS) {
                switch (key) {
                    case GLFW.GLFW_KEY_R -> colorManager.setColor(LIGHT_RED);
                    case GLFW.GLFW_KEY_G ->
                            colorManager.setColor(((mods & GLFW.GLFW_MOD_CONTROL) == 0) ? Color.LIGHT_GRAY : LIGHT_GREEN);
                    case GLFW.GLFW_KEY_B -> colorManager.setColor(LIGHT_BLUE);
                    case GLFW.GLFW_KEY_W -> colorManager.setColor(Color.WHITE);
                    case GLFW.GLFW_KEY_P -> colorManager.setColor(LIGHT_PURPLE);
                    case GLFW.GLFW_KEY_M -> colorManager.setColor(LIGHT_MANGO);
                    case GLFW.GLFW_KEY_V -> colorManager.setColor(LIGHT_VIOLET);
                    case GLFW.GLFW_KEY_C -> colorManager.setColor(Color.CYAN);
                    case GLFW.GLFW_KEY_O -> colorManager.setColor(Color.ORANGE);
                }
            }

            switch (key) {
                case GLFW.GLFW_KEY_ESCAPE, GLFW.GLFW_KEY_Q -> GLFW.glfwSetWindowShouldClose(window1, true);
            }
        });

        while (!GLFW.glfwWindowShouldClose(window)) {
            Thread.onSpinWait();
            GLFW.glfwPollEvents();

            if (GLFW.glfwGetKey(window, GLFW.GLFW_KEY_ESCAPE) == GLFW.GLFW_PRESS) {
                GLFW.glfwSetWindowShouldClose(window, true);
            }
        }

        GLFW.glfwTerminate();
    }

    @RequiredArgsConstructor
    static class ColorManager {
        final long window;

        void setColor(Color color) {
            GL11C.glClearColor(
                    (float) color.getRed() / 255,
                    (float) color.getGreen() / 255,
                    (float) color.getBlue() / 255,
                    1.0f
            );
            GL11C.glClear(GL11C.GL_COLOR_BUFFER_BIT);
            GLFW.glfwSwapBuffers(window);
        }
    }
}