Help with opening minecraft in eclipse

Hello, I am having trouble with opening minecraft in eclipse, whenever I try to run minecraft, this comes out of the console:
 

[2020-09-04 16:50:54] [INFO   ] Natives: E:\forge-1.12.2-14.23.5.2854-mdk\build\natives
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by net.minecraftforge.legacydev.MainClient (file:/C:/Users/Johncito/.gradle/caches/modules-2/files-2.1/net.minecraftforge/legacydev/0.2.3.1/f2cd4a8c9f09faf1c1e4a9a4c65df36e634f95db/legacydev-0.2.3.1-fatjar.jar) to method java.lang.ClassLoader.initializePath(java.lang.String)
WARNING: Please consider reporting this to the maintainers of net.minecraftforge.legacydev.MainClient
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
[2020-09-04 16:50:54] [INFO   ] Main Class: net.minecraft.launchwrapper.Launch
[2020-09-04 16:50:54] [INFO   ] Srg2Mcp: E:\forge-1.12.2-14.23.5.2854-mdk\build\createSrgToMcp\output.srg
[2020-09-04 16:50:54] [INFO   ] Extra: []
[2020-09-04 16:50:54] [INFO   ] Running with arguments: [--version, 1.12, --assetIndex, 1.12, --assetsDir, C:\Users\Johncito\.gradle\caches\forge_gradle\assets, --accessToken, {REDACTED}, --userProperties, [], --tweakClass, net.minecraftforge.fml.common.launcher.FMLTweaker]
Exception in thread "main" 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 net.minecraftforge.legacydev.Main.start(Main.java:86)
    at net.minecraftforge.legacydev.MainClient.main(MainClient.java:29)
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

Can anyone help me? I have no idea on what to do.

Thanks in advance!