http://xml.apache.org/commons/components/external/: xml-commons provides an Apache-hosted set of DOM, SAX, and JAXP interfaces for use in other xml-based projects. Our hope is that we can standardize on both a common version and packaging scheme for these critical XML standards interfaces to make the lives of both our developers and users easier. The External Components portion of xml-commons contains interfaces that are defined by external standards organizations. For DOM, that's the W3C; for SAX it's David Megginson and sax.sourceforge.net; for JAXP it's Sun. 
public abstract class javax.xml.validation.TypeInfoProvider
  minor version: 0
  major version: 59
  flags: flags: (0x0421) ACC_PUBLIC, ACC_SUPER, ACC_ABSTRACT
  this_class: javax.xml.validation.TypeInfoProvider
  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 // javax.xml.validation.TypeInfoProvider this
         0: .line 50
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 51
            return
        end local 0 // javax.xml.validation.TypeInfoProvider this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Ljavax/xml/validation/TypeInfoProvider;

  public abstract org.w3c.dom.TypeInfo getElementTypeInfo();
    descriptor: ()Lorg/w3c/dom/TypeInfo;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT

  public abstract org.w3c.dom.TypeInfo getAttributeTypeInfo(int);
    descriptor: (I)Lorg/w3c/dom/TypeInfo;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    MethodParameters:
       Name  Flags
      index  

  public abstract boolean isIdAttribute(int);
    descriptor: (I)Z
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    MethodParameters:
       Name  Flags
      index  

  public abstract boolean isSpecified(int);
    descriptor: (I)Z
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    MethodParameters:
       Name  Flags
      index  
}
SourceFile: "TypeInfoProvider.java"