https://xerces.apache.org/xerces2-j/: Xerces2 is the next generation of high performance, fully compliant XML parsers in the Apache Xerces family. This new version of Xerces introduces the Xerces Native Interface (XNI), a complete framework for building parser components and configurations that is extremely modular and easy to program. The Apache Xerces2 parser is the reference implementation of XNI but other parser components, configurations, and parsers can be written using the Xerces Native Interface. For complete design and implementation documents, refer to the XNI Manual. Xerces2 is a fully conforming XML Schema 1.0 processor. A partial experimental implementation of the XML Schema 1.1 Structures and Datatypes Working Drafts (December 2009) and an experimental implementation of the XML Schema Definition Language (XSD): Component Designators (SCD) Candidate Recommendation (January 2010) are provided for evaluation. For more information, refer to the XML Schema page. Xerces2 also provides a complete implementation of the Document Object Model Level 3 Core and Load/Save W3C Recommendations and provides a complete implementation of the XML Inclusions (XInclude) W3C Recommendation. It also provides support for OASIS XML Catalogs v1.1. Xerces2 is able to parse documents written according to the XML 1.1 Recommendation, except that it does not yet provide an option to enable normalization checking as described in section 2.13 of this specification. It also handles namespaces according to the XML Namespaces 1.1 Recommendation, and will correctly serialize XML 1.1 documents if the DOM level 3 load/save APIs are in use. 
public abstract class org.apache.xerces.impl.dv.DTDDVFactory
  minor version: 0
  major version: 59
  flags: flags: (0x0421) ACC_PUBLIC, ACC_SUPER, ACC_ABSTRACT
  this_class: org.apache.xerces.impl.dv.DTDDVFactory
  super_class: java.lang.Object
{
  private static final java.lang.String DEFAULT_FACTORY_CLASS;
    descriptor: Ljava/lang/String;
    flags: (0x001a) ACC_PRIVATE, ACC_STATIC, ACC_FINAL
    ConstantValue: "org.apache.xerces.impl.dv.dtd.DTDDVFactoryImpl"

  public static final org.apache.xerces.impl.dv.DTDDVFactory getInstance();
    descriptor: ()Lorg/apache/xerces/impl/dv/DTDDVFactory;
    flags: (0x0019) ACC_PUBLIC, ACC_STATIC, ACC_FINAL
    Code:
      stack=1, locals=0, args_size=0
         0: .line 45
            ldc "org.apache.xerces.impl.dv.dtd.DTDDVFactoryImpl"
            invokestatic org.apache.xerces.impl.dv.DTDDVFactory.getInstance:(Ljava/lang/String;)Lorg/apache/xerces/impl/dv/DTDDVFactory;
            areturn
      LocalVariableTable:
        Start  End  Slot  Name  Signature
    Exceptions:
      throws org.apache.xerces.impl.dv.DVFactoryException

  public static final org.apache.xerces.impl.dv.DTDDVFactory getInstance(java.lang.String);
    descriptor: (Ljava/lang/String;)Lorg/apache/xerces/impl/dv/DTDDVFactory;
    flags: (0x0019) ACC_PUBLIC, ACC_STATIC, ACC_FINAL
    Code:
      stack=5, locals=1, args_size=1
        start local 0 // java.lang.String factoryClass
         0: .line 60
            aload 0 /* factoryClass */
            invokestatic org.apache.xerces.impl.dv.ObjectFactory.findClassLoader:()Ljava/lang/ClassLoader;
            iconst_1
            invokestatic org.apache.xerces.impl.dv.ObjectFactory.newInstance:(Ljava/lang/String;Ljava/lang/ClassLoader;Z)Ljava/lang/Object;
         1: .line 59
            checkcast org.apache.xerces.impl.dv.DTDDVFactory
         2: areturn
         3: .line 62
      StackMap locals:
      StackMap stack: java.lang.ClassCastException
            pop
         4: .line 63
            new org.apache.xerces.impl.dv.DVFactoryException
            dup
            new java.lang.StringBuilder
            dup
            ldc "DTD factory class "
            invokespecial java.lang.StringBuilder.<init>:(Ljava/lang/String;)V
            aload 0 /* factoryClass */
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
            ldc " does not extend from DTDDVFactory."
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
            invokevirtual java.lang.StringBuilder.toString:()Ljava/lang/String;
            invokespecial org.apache.xerces.impl.dv.DVFactoryException.<init>:(Ljava/lang/String;)V
            athrow
        end local 0 // java.lang.String factoryClass
      LocalVariableTable:
        Start  End  Slot          Name  Signature
            0    5     0  factoryClass  Ljava/lang/String;
      Exception table:
        from    to  target  type
           0     2       3  Class java.lang.ClassCastException
    Exceptions:
      throws org.apache.xerces.impl.dv.DVFactoryException
    MethodParameters:
              Name  Flags
      factoryClass  

  protected void <init>();
    descriptor: ()V
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // org.apache.xerces.impl.dv.DTDDVFactory this
         0: .line 68
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
            return
        end local 0 // org.apache.xerces.impl.dv.DTDDVFactory this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lorg/apache/xerces/impl/dv/DTDDVFactory;

  public abstract org.apache.xerces.impl.dv.DatatypeValidator getBuiltInDV(java.lang.String);
    descriptor: (Ljava/lang/String;)Lorg/apache/xerces/impl/dv/DatatypeValidator;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    MethodParameters:
      Name  Flags
      name  

  public abstract java.util.Hashtable getBuiltInTypes();
    descriptor: ()Ljava/util/Hashtable;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
}
SourceFile: "DTDDVFactory.java"