Common issues

Note: The character "$" represents a part of the error that could change, that is still the error you are looking for, and the specified fix should work for you

java.lang.UnsatisfiedLinkError: no $ in java.library.path (IntelliJ Idea)

Note: this error's "$" is often "lwjgl" or "lwjgl64"

If you are encountering this issue it means you haven't set the working directory to the MCP's jars folder.

Fix

1. Edit your run configuration
2. Change the working directory with "MCP_LOC\jars", where "MCP_LOC" is the location you have decompiled the MCP in

Unrecognized option: -Xincgc (Eclipse)

This is caused by a default argument that is not supported by the jre you are using. It could mean you're using Eclipse's jdk, which is 11 or higher. There are two ways to fix this issue The first one requires you to change the used jdk to 8. (Even if you only have Java 8 installed, it doesn't mean that that's what eclipse is going to default to. In fact, newer versions of Eclipse comes with jdk 11 bundled and used by default.)

Fix 2

1. Click on the arrow key next to the "Run" button
2. Click on "Run Configuration..."
3. Click on "Arguments"
4. Remove "-Xincgc " from the "VM Arguments", leaving no space before the next argument

Unable to add $ to system class path - the system class loader does not define the appendToClassPathForInstrumentation method or the method failed

This might be caused by a Non-ASCII character present in your Eclipse installation path.

Possible Fix:

Re-install Eclipse with a different path, that contains ASCII characters only.