Why does Minecraft keep crashing in Ubuntu 14.04?

I just installed Minecraft on my Ubuntu system using the Minecraft Installer Peeps PPA. When Minecraft finished downloading and was launched, it crashed and this is what I got:

    ---- Minecraft Crash Report ----
// Daisy, daisy...

Time: 10/12/15 5:25 PM
Description: Initializing game

java.lang.ExceptionInInitializerError
    at ave.ar(SourceFile:560)
    at ave.am(SourceFile:361)
    at ave.a(SourceFile:310)
    at net.minecraft.client.main.Main.main(SourceFile:124)
Caused by: java.lang.ArrayIndexOutOfBoundsException: 0
    at org.lwjgl.opengl.LinuxDisplay.getAvailableDisplayModes(LinuxDisplay.java:951)
    at org.lwjgl.opengl.LinuxDisplay.init(LinuxDisplay.java:738)
    at org.lwjgl.opengl.Display.<clinit>(Display.java:138)
    ... 4 more


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Stacktrace:
    at ave.ar(SourceFile:560)
    at ave.am(SourceFile:361)

-- Initialization --
Details:
Stacktrace:
    at ave.a(SourceFile:310)
    at net.minecraft.client.main.Main.main(SourceFile:124)

-- System Details --
Details:
    Minecraft Version: 1.8.8
    Operating System: Linux (amd64) version 3.19.0-30-generic
    Java Version: 1.7.0_79, Oracle Corporation
    Java VM Version: OpenJDK 64-Bit Server VM (mixed mode), Oracle Corporation
    Memory: 67187144 bytes (64 MB) / 158736384 bytes (151 MB) up to 1060372480 bytes (1011 MB)
    JVM Flags: 5 total; -Xmx1G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
    IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
    Launched Version: 1.8.8
    LWJGL: 2.9.4
    OpenGL: ~~ERROR~~ RuntimeException: No OpenGL context found in the current thread.
    GL Caps: 
    Using VBOs: No
    Is Modded: Probably not. Jar signature remains and client brand is untouched.
    Type: Client (map_client.txt)
    Resource Packs: 
    Current Language: ~~ERROR~~ NullPointerException: null
    Profiler Position: N/A (disabled)
    CPU: <unknown>

Does anyone know why this is happening? Thanks.

1. Looks like it's an OpenGL issue. Try sudo aptitude install freeglut3
2. Check if you have the appropriate backport in your sources.list. I think that Debian's wiki explains it better.
3. Check if you have OpenJDK 8 sudo aptitude install openjdk-8-jre
4. Uninstall OpenJDK 7 sudo aptitude purge openjdk-7-jre

It seems like you're missing XRandR. You can get it by running:

sudo apt-get install x11-xserver-utils

For details, see this forum thread.