Class ClasspathUrls

java.lang.Object
com.hloader.launch.ClasspathUrls
public final class ClasspathUrls extends Object
Produces a URLClassLoader whose URLClassLoader.getURLs() reports the JVM's actual -cp entries. LegacyClassLoaderCastTransformer calls wrap() in place of code that does (URLClassLoader) someClass.getClassLoader() - a pattern old, pre-1.6 Minecraft versions use (via net.minecraft.launchwrapper.Launch) to read back the classpath, which throws a ClassCastException on Java 9+ because the real system class loader stopped being a URLClassLoader. Setting -Djava.system.class.loader to a URLClassLoader subclass does *not* fix this: on modern JDKs the main class is loaded by the true built-in system loader before that property ever takes effect, so Launch.class.getClassLoader() still returns the non-URLClassLoader instance regardless. Patching the bytecode is the only reliable fix.