https://www.graalvm.org/ 
public interface com.oracle.truffle.llvm.runtime.ContextExtension$Factory<C extends com.oracle.truffle.llvm.runtime.ContextExtension>
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: com.oracle.truffle.llvm.runtime.ContextExtension$Factory
  super_class: java.lang.Object
{
  public abstract C create(com.oracle.truffle.api.TruffleLanguage$Env);
    descriptor: (Lcom/oracle/truffle/api/TruffleLanguage$Env;)Lcom/oracle/truffle/llvm/runtime/ContextExtension;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    Signature: (Lcom/oracle/truffle/api/TruffleLanguage$Env;)TC;
    MethodParameters:
      Name  Flags
      env   
}
Signature: <C::Lcom/oracle/truffle/llvm/runtime/ContextExtension;>Ljava/lang/Object;
SourceFile: "ContextExtension.java"
NestHost: com.oracle.truffle.llvm.runtime.ContextExtension
InnerClasses:
  public final Env = com.oracle.truffle.api.TruffleLanguage$Env of com.oracle.truffle.api.TruffleLanguage
  public abstract Factory = com.oracle.truffle.llvm.runtime.ContextExtension$Factory of com.oracle.truffle.llvm.runtime.ContextExtension
    RuntimeVisibleAnnotations: 
      java.lang.FunctionalInterface()