https://github.com/google/guava/guava: Guava is a suite of core and expanded libraries that include utility classes, google's collections, io classes, and much much more. 
public interface com.google.common.util.concurrent.FutureCallback<V>
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: com.google.common.util.concurrent.FutureCallback
  super_class: java.lang.Object
{
  public abstract void onSuccess();
    descriptor: (Ljava/lang/Object;)V
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    Signature: (TV;)V
    RuntimeVisibleTypeAnnotations: 
      METHOD_FORMAL_PARAMETER
        org.checkerframework.checker.nullness.qual.Nullable()
    MethodParameters:
        Name  Flags
      result  

  public abstract void onFailure(java.lang.Throwable);
    descriptor: (Ljava/lang/Throwable;)V
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    MethodParameters:
      Name  Flags
      t     
}
Signature: <V:Ljava/lang/Object;>Ljava/lang/Object;
SourceFile: "FutureCallback.java"
    RuntimeInvisibleAnnotations: 
      com.google.common.annotations.GwtCompatible()