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 abstract class com.google.common.collect.ForwardingObject
  minor version: 0
  major version: 59
  flags: flags: (0x0421) ACC_PUBLIC, ACC_SUPER, ACC_ABSTRACT
  this_class: com.google.common.collect.ForwardingObject
  super_class: java.lang.Object
{
  protected void <init>();
    descriptor: ()V
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.collect.ForwardingObject this
         0: .line 50
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
            return
        end local 0 // com.google.common.collect.ForwardingObject this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/collect/ForwardingObject;

  protected abstract java.lang.Object delegate();
    descriptor: ()Ljava/lang/Object;
    flags: (0x0404) ACC_PROTECTED, ACC_ABSTRACT

  public java.lang.String toString();
    descriptor: ()Ljava/lang/String;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.collect.ForwardingObject this
         0: .line 63
            aload 0 /* this */
            invokevirtual com.google.common.collect.ForwardingObject.delegate:()Ljava/lang/Object;
            invokevirtual java.lang.Object.toString:()Ljava/lang/String;
            areturn
        end local 0 // com.google.common.collect.ForwardingObject this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/collect/ForwardingObject;
}
SourceFile: "ForwardingObject.java"
    RuntimeInvisibleAnnotations: 
      com.google.common.annotations.GwtCompatible()