Ugdhar

Show the output of java -version It's possible that even though you have 8 on there too, 9 is first in the path and is the one being used to launch. Double check your path to make sure it's pointing to java 8, and/or remove java 9, and see what happens.

If you username is username@email.com and your password is password, you should be adding --username=username@email.com --password=password Is that how you're doing it in the argument box?

In eclipse, Run->Run Configurations, then after you select the configuration you are using the launch the client on the left, choose the Arguments tab, and the --username and --password arguments go in the program arguments box.

You have a mod for 1.6.4 trying to load on 1.12.2, try removing that and seeing if the problem still persists.

Is it possible to try with Oracle JDK instead of OpenJDK? It should work either way, but the official advice I've seen says to use Oracle. Might be worth a try

It will be in the minecraft profile directory\logs (same folder that contains the mods folder will contain the logs folder) Make sure you post it in spoiler tags (the eyeball button)

Please post your logs/fml-client-latest.log

First, I would try to update away from 1.8.9, it's getting pretty old and will probably stop being supported here much as 1.7.10 has. Are you using a texture or resource pack of some kind? If so, I would try just using the standard minecraft graphics and see what happens.

Post the fml-server-latest.log file please

https://docs.oracle.com/javase/tutorial/

Looks like DeltaRPG this time, remove that, try again, if it still crashes, post the new log

Post the new log after removing that mod. You could try with no mods, and add them in 1 by 1, trying in between, and if it crashes, you'll know which mod you just added that caused the crash.

Please post the fml-client-latest.log (in the logs folder) in spoiler tags. It should give more info on what's up.

I believe you need to override transferStackInSlot in your container class. You can probably find an example in a vanilla container class

Try it, it sounds more logical (I haven't messed with entity joining events at all, so not sure myself), EntityEvent makes it sound like it will fire for ANYTHING related to entities, spawning, dying, joining the world, maybe even moving. The name of the method doesn't matter, it's having the @SubscribeEvent notation and the proper parameters that make it work.

That hs_err_pid2676.mdmp file is a memory dump file, honestly it wouldn't do you any good opening it anyway. If you still want to, just get a hex editor and open it up. It's not like a txt file, it's a binary dump of what was in memory when stuff crashed, so it won't really be human readable.

I would just use the Forge Energy capability API. Doesn't have any dependencies, and as far as I know is compatible with RF in recent versions. I was tinkering with energy a bit recently, and the generator I made was able to supply power to machines from ThermalExpansion. I know that's not a definitive "it's globally compatible" or anything, but it at least demonstrates it works with stuff other people made.

Please post the entire fml-client-latest.log in spoiler tags *edit: Also, 1.7.10 is no longer supported, so you won't get help for it here.

It's all in the github repo there, just browse around the source files

I've been creating my creative tab right in my mod class near the top: public static final CreativeTabs TEST_TAB = new CreativeTabs("test") { @SideOnly(Side.CLIENT) public ItemStack getTabIconItem() { return new ItemStack(Items.REDSTONE); } }; I haven't messed with it much, but I do recall it wouldn't use my test item for the tab icon because my items hadn't registered yet, and I haven't as of yet bothered to try and fix/change/figure it out. But besides that works fine as far as I can see.

Look for "targetCompatability" in your build.gradle, see if you can change it to 1.8 there.

This link has a great example of using registry events to register stuff.

I also see net.minecraftforge.fml.common.MissingModsException: Mod twilightforest (The Twilight Forest) requires [forge@[14.23.0.2501,)] And you're running forge 14.23.0.2491

Please upload your code to a github (http://www.github.com), we're going to need to see pretty much every class because everything in your code calls/references something else, and we need to see how it fits together to see where your null is.

Post your entire fml-client-latest.log file in spoiler tags please