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. 
class com.google.common.io.FileBackedOutputStream$2 extends com.google.common.io.ByteSource
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: com.google.common.io.FileBackedOutputStream$2
  super_class: com.google.common.io.ByteSource
{
  final com.google.common.io.FileBackedOutputStream this$0;
    descriptor: Lcom/google/common/io/FileBackedOutputStream;
    flags: (0x1010) ACC_FINAL, ACC_SYNTHETIC

  void <init>(com.google.common.io.FileBackedOutputStream);
    descriptor: (Lcom/google/common/io/FileBackedOutputStream;)V
    flags: (0x0000) 
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // com.google.common.io.FileBackedOutputStream$2 this
         0: .line 111
            aload 0 /* this */
            aload 1
            putfield com.google.common.io.FileBackedOutputStream$2.this$0:Lcom/google/common/io/FileBackedOutputStream;
            aload 0 /* this */
            invokespecial com.google.common.io.ByteSource.<init>:()V
            return
        end local 0 // com.google.common.io.FileBackedOutputStream$2 this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/io/FileBackedOutputStream$2;
    MethodParameters:
        Name  Flags
      this$0  final

  public java.io.InputStream openStream();
    descriptor: ()Ljava/io/InputStream;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.io.FileBackedOutputStream$2 this
         0: .line 114
            aload 0 /* this */
            getfield com.google.common.io.FileBackedOutputStream$2.this$0:Lcom/google/common/io/FileBackedOutputStream;
            invokevirtual com.google.common.io.FileBackedOutputStream.openInputStream:()Ljava/io/InputStream;
            areturn
        end local 0 // com.google.common.io.FileBackedOutputStream$2 this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/io/FileBackedOutputStream$2;
    Exceptions:
      throws java.io.IOException
}
SourceFile: "FileBackedOutputStream.java"
EnclosingMethod: com.google.common.io.FileBackedOutputStream.<init>:(IZ)V
NestHost: com.google.common.io.FileBackedOutputStream
InnerClasses:
  com.google.common.io.FileBackedOutputStream$2