Assistance with forge server...

Hello, I am trying to run a Minecraft forge server on a mac running el cap. I have succeeded with setting up the server and running it, but i need to allocate more ram. I have tried the commands and scripts to start the jar file running the memory arguments, but the start command file fails to start the server. I believe it is something to do with my java version so would someone be willing to help me figure out how to solve my problem? I am running the most current version of java and my Minecraft version is 1.7.10. I am also running the latest version of forge for 1.7.10. The server start script is inside the server folder and this is the code #!/bin/bash
cd "$(dirname "$0")"
exec java -Xms2G -Xmx2G -jar forgeServer.jar gui

this is the output...

/Users/elserjustin/Desktop/server/start.command ; exit;

A problem occurred running the Server launcher.java.lang.reflect.InvocationTargetException

at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.base/java.lang.reflect.Method.invoke(Method.java:564)

at cpw.mods.fml.relauncher.ServerLaunchWrapper.run(ServerLaunchWrapper.java:43)

at cpw.mods.fml.relauncher.ServerLaunchWrapper.main(ServerLaunchWrapper.java:12)

Caused by: java.lang.ClassCastException: class jdk.internal.loader.ClassLoaders$AppClassLoader cannot be cast to class java.net.URLClassLoader (jdk.internal.loader.ClassLoaders$AppClassLoader and java.net.URLClassLoader are in module java.base of loader 'bootstrap')

at net.minecraft.launchwrapper.Launch.<init>(Launch.java:34)

at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

... 6 more

logout

Saving session...

...copying shared history...

...saving history...truncating history files...

...completed.

[Process completed]

Any help is appreciated!