After I had downloaded the newest server available on Minecraft.net, I found out that my server no longer runs properly. Every time I start minecraft_server.jar it would run for ~1 seconds before it abruptly closes out. I took a screenshot just milliseconds before it crashes again, and the last line is always "Using default channel type" before the said crash. I've included screenshots that I believe are relevant.
I've also followed LBEGaming's Server Update tutorial step from step, and it had always worked no problems until now: