Installing 1.8/1.12 on Manjaro Linux

[BattleBred]

I got the recommended installer for 1.8 and 1.12 but neither of them worked, I simply got the error messages

 [name@pc Downloads]$ java -jar forge-1.8-11.14.4.1563-installer.jar
Setting up logger: /home/manuel/Downloads/forge-1.8-11.14.4.1563-installer.jar.log
Exception in thread "main" java.lang.ExceptionInInitializerError
    at net.minecraftforge.installer.ClientInstall.getSponsorMessage(ClientInstall.java:326)
    at net.minecraftforge.installer.InstallerAction.getSponsorMessage(InstallerAction.java:59)
    at net.minecraftforge.installer.InstallerPanel.updateFilePath(InstallerPanel.java:236)
    at net.minecraftforge.installer.InstallerPanel.<init>(InstallerPanel.java:217)
    at net.minecraftforge.installer.SimpleInstaller.launchGui(SimpleInstaller.java:153)
    at net.minecraftforge.installer.SimpleInstaller.main(SimpleInstaller.java:40)
Caused by: java.lang.ArrayIndexOutOfBoundsException: 1
    at net.minecraftforge.installer.MirrorData.buildMirrorList(MirrorData.java:84)
    at net.minecraftforge.installer.MirrorData.<init>(MirrorData.java:63)
    at net.minecraftforge.installer.MirrorData.<clinit>(MirrorData.java:17)
    ... 6 more

[name@pc Downloads]$ java -jar forge-1.12-14.21.1.2387-installer.jar
Setting up logger: /home/manuel/Downloads/forge-1.12-14.21.1.2387-installer.jar.log
Exception in thread "main" java.lang.ExceptionInInitializerError
    at net.minecraftforge.installer.ClientInstall.getSponsorMessage(ClientInstall.java:401)
    at net.minecraftforge.installer.InstallerAction.getSponsorMessage(InstallerAction.java:60)
    at net.minecraftforge.installer.InstallerPanel.updateFilePath(InstallerPanel.java:334)
    at net.minecraftforge.installer.InstallerPanel.<init>(InstallerPanel.java:315)
    at net.minecraftforge.installer.SimpleInstaller.launchGui(SimpleInstaller.java:164)
    at net.minecraftforge.installer.SimpleInstaller.main(SimpleInstaller.java:51)
Caused by: java.lang.ArrayIndexOutOfBoundsException: 1
    at net.minecraftforge.installer.MirrorData.buildMirrorList(MirrorData.java:84)
    at net.minecraftforge.installer.MirrorData.<init>(MirrorData.java:63)
    at net.minecraftforge.installer.MirrorData.<clinit>(MirrorData.java:17)
    ... 6 more

What do i do?

[DaemonUmbra]

Really old Minecraft versions are no longer supported on this forum.

Please update to a modern version of Minecraft to receive support.