https://lucene.apache.org/lucene-parent/lucene-codecs: Codecs and postings formats for Apache Lucene. (The Apache Software Foundation) 
abstract class org.apache.lucene.codecs.memory.LegacyNumericDocValues
  minor version: 0
  major version: 59
  flags: flags: (0x0420) ACC_SUPER, ACC_ABSTRACT
  this_class: org.apache.lucene.codecs.memory.LegacyNumericDocValues
  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 // org.apache.lucene.codecs.memory.LegacyNumericDocValues this
         0: .line 31
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
            return
        end local 0 // org.apache.lucene.codecs.memory.LegacyNumericDocValues this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lorg/apache/lucene/codecs/memory/LegacyNumericDocValues;

  public abstract long get(int);
    descriptor: (I)J
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    MethodParameters:
       Name  Flags
      docID  
}
SourceFile: "LegacyNumericDocValues.java"
    RuntimeVisibleAnnotations: 
      java.lang.Deprecated()