Im new to forge and have downloaded the latest version of the installer, however whenever I run it all it does is create a 2kb notepad file name "installer" with this inside:

 

Exception in thread "main" java.lang.Error: Trampoline must not be defined by the bootstrap classloader
    at sun.reflect.misc.Trampoline.<clinit>(Unknown Source)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Unknown Source)
    at sun.reflect.misc.MethodUtil.getTrampolineClass(Unknown Source)
    at sun.reflect.misc.MethodUtil.access$000(Unknown Source)
    at sun.reflect.misc.MethodUtil$1.run(Unknown Source)
    at sun.reflect.misc.MethodUtil$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.reflect.misc.MethodUtil.getTrampoline(Unknown Source)
    at sun.reflect.misc.MethodUtil.<clinit>(Unknown Source)
    at javax.swing.UIDefaults.getUI(Unknown Source)
    at javax.swing.UIManager.getUI(Unknown Source)
    at javax.swing.JPanel.updateUI(Unknown Source)
    at javax.swing.JPanel.<init>(Unknown Source)
    at javax.swing.JPanel.<init>(Unknown Source)
    at javax.swing.JPanel.<init>(Unknown Source)
    at net.minecraftforge.installer.InstallerPanel.<init>(InstallerPanel.java:126)
    at net.minecraftforge.installer.SimpleInstaller.launchGui(SimpleInstaller.java:164)
    at net.minecraftforge.installer.SimpleInstaller.main(SimpleInstaller.java:51)
 

I have tried using the "recommend" installer and just a random older one, which all ran into the same issue.

Edited July 10, 20178 yr by Blam Blam!

I have no idea, how would I check?

8.0.1210.13

My bad, Update 121

All is working now, thanks for the help. I,ll make sure to check if java is up to date next time