https://source.android.com/ 
public abstract class android.telecom.Conferenceable
  minor version: 0
  major version: 59
  flags: flags: (0x0421) ACC_PUBLIC, ACC_SUPER, ACC_ABSTRACT
  this_class: android.telecom.Conferenceable
  super_class: java.lang.Object
{
  void <init>();
    descriptor: ()V
    flags: (0x0000) 
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // android.telecom.Conferenceable this
         0: .line 25
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
            return
        end local 0 // android.telecom.Conferenceable this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Landroid/telecom/Conferenceable;
}
SourceFile: "Conferenceable.java"