http://lucene.apache.org/lucene-parent/lucene-core: Apache Lucene Java Core (The Apache Software Foundation) 
public final class org.apache.lucene.index.IndexReader$CacheKey
  minor version: 0
  major version: 59
  flags: flags: (0x0031) ACC_PUBLIC, ACC_FINAL, ACC_SUPER
  this_class: org.apache.lucene.index.IndexReader$CacheKey
  super_class: java.lang.Object
{
  void <init>();
    descriptor: ()V
    flags: (0x0000) 
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // org.apache.lucene.index.IndexReader$CacheKey this
         0: .line 115
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
            return
        end local 0 // org.apache.lucene.index.IndexReader$CacheKey this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lorg/apache/lucene/index/IndexReader$CacheKey;
}
SourceFile: "IndexReader.java"
NestHost: org.apache.lucene.index.IndexReader
InnerClasses:
  public final CacheKey = org.apache.lucene.index.IndexReader$CacheKey of org.apache.lucene.index.IndexReader