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 final class com.google.common.cache.RemovalListeners
  minor version: 0
  major version: 59
  flags: flags: (0x0031) ACC_PUBLIC, ACC_FINAL, ACC_SUPER
  this_class: com.google.common.cache.RemovalListeners
  super_class: java.lang.Object
{
  private void <init>();
    descriptor: ()V
    flags: (0x0002) ACC_PRIVATE
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.cache.RemovalListeners this
         0: .line 31
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
            return
        end local 0 // com.google.common.cache.RemovalListeners this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/cache/RemovalListeners;

  public static <K, V> com.google.common.cache.RemovalListener<K, V> asynchronous(com.google.common.cache.RemovalListener<K, V>, java.util.concurrent.Executor);
    descriptor: (Lcom/google/common/cache/RemovalListener;Ljava/util/concurrent/Executor;)Lcom/google/common/cache/RemovalListener;
    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
    Code:
      stack=4, locals=2, args_size=2
        start local 0 // com.google.common.cache.RemovalListener listener
        start local 1 // java.util.concurrent.Executor executor
         0: .line 42
            aload 0 /* listener */
            invokestatic com.google.common.base.Preconditions.checkNotNull:(Ljava/lang/Object;)Ljava/lang/Object;
            pop
         1: .line 43
            aload 1 /* executor */
            invokestatic com.google.common.base.Preconditions.checkNotNull:(Ljava/lang/Object;)Ljava/lang/Object;
            pop
         2: .line 44
            new com.google.common.cache.RemovalListeners$1
            dup
            aload 1 /* executor */
            aload 0 /* listener */
            invokespecial com.google.common.cache.RemovalListeners$1.<init>:(Ljava/util/concurrent/Executor;Lcom/google/common/cache/RemovalListener;)V
            areturn
        end local 1 // java.util.concurrent.Executor executor
        end local 0 // com.google.common.cache.RemovalListener listener
      LocalVariableTable:
        Start  End  Slot      Name  Signature
            0    3     0  listener  Lcom/google/common/cache/RemovalListener<TK;TV;>;
            0    3     1  executor  Ljava/util/concurrent/Executor;
    Signature: <K:Ljava/lang/Object;V:Ljava/lang/Object;>(Lcom/google/common/cache/RemovalListener<TK;TV;>;Ljava/util/concurrent/Executor;)Lcom/google/common/cache/RemovalListener<TK;TV;>;
    MethodParameters:
          Name  Flags
      listener  final
      executor  final
}
SourceFile: "RemovalListeners.java"
NestMembers:
  com.google.common.cache.RemovalListeners$1  com.google.common.cache.RemovalListeners$1$1
InnerClasses:
  com.google.common.cache.RemovalListeners$1
    RuntimeInvisibleAnnotations: 
      com.google.common.annotations.GwtIncompatible()