https://source.android.com/ 
interface android.provider.ContactsContract$ContactCounts
  minor version: 0
  major version: 59
  flags: flags: (0x0600) ACC_INTERFACE, ACC_ABSTRACT
  this_class: android.provider.ContactsContract$ContactCounts
  super_class: java.lang.Object
{
  public static final java.lang.String EXTRA_ADDRESS_BOOK_INDEX;
    descriptor: Ljava/lang/String;
    flags: (0x0019) ACC_PUBLIC, ACC_STATIC, ACC_FINAL
    ConstantValue: "android.provider.extra.ADDRESS_BOOK_INDEX"

  public static final java.lang.String EXTRA_ADDRESS_BOOK_INDEX_TITLES;
    descriptor: Ljava/lang/String;
    flags: (0x0019) ACC_PUBLIC, ACC_STATIC, ACC_FINAL
    ConstantValue: "android.provider.extra.ADDRESS_BOOK_INDEX_TITLES"

  public static final java.lang.String EXTRA_ADDRESS_BOOK_INDEX_COUNTS;
    descriptor: Ljava/lang/String;
    flags: (0x0019) ACC_PUBLIC, ACC_STATIC, ACC_FINAL
    ConstantValue: "android.provider.extra.ADDRESS_BOOK_INDEX_COUNTS"
}
SourceFile: "ContactsContract.java"
NestHost: android.provider.ContactsContract
InnerClasses:
  abstract ContactCounts = android.provider.ContactsContract$ContactCounts of android.provider.ContactsContract