https://github.com/oracle/graal: GraalVM is an ecosystem for compiling and running applications written in multiple languages. GraalVM removes the isolation between programming languages and enables interoperability in a shared runtime. 
public interface org.graalvm.nativeimage.Threading$RecurringCallback
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: org.graalvm.nativeimage.Threading$RecurringCallback
  super_class: java.lang.Object
{
  public abstract void run(org.graalvm.nativeimage.Threading$RecurringCallbackAccess);
    descriptor: (Lorg/graalvm/nativeimage/Threading$RecurringCallbackAccess;)V
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    MethodParameters:
        Name  Flags
      access  
}
SourceFile: "Threading.java"
NestHost: org.graalvm.nativeimage.Threading
InnerClasses:
  public abstract RecurringCallback = org.graalvm.nativeimage.Threading$RecurringCallback of org.graalvm.nativeimage.Threading
  public abstract RecurringCallbackAccess = org.graalvm.nativeimage.Threading$RecurringCallbackAccess of org.graalvm.nativeimage.Threading
    RuntimeVisibleAnnotations: 
      java.lang.FunctionalInterface()