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. 
class javax.xml.datatype.FactoryFinder$ConfigurationError extends java.lang.Error
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: javax.xml.datatype.FactoryFinder$ConfigurationError
  super_class: java.lang.Error
{
  private static final long serialVersionUID;
    descriptor: J
    flags: (0x001a) ACC_PRIVATE, ACC_STATIC, ACC_FINAL
    ConstantValue: -3644413026244211347

  private java.lang.Exception exception;
    descriptor: Ljava/lang/Exception;
    flags: (0x0002) ACC_PRIVATE

  void <init>(java.lang.String, java.lang.Exception);
    descriptor: (Ljava/lang/String;Ljava/lang/Exception;)V
    flags: (0x0000) 
    Code:
      stack=2, locals=3, args_size=3
        start local 0 // javax.xml.datatype.FactoryFinder$ConfigurationError this
        start local 1 // java.lang.String msg
        start local 2 // java.lang.Exception x
         0: .line 339
            aload 0 /* this */
            aload 1 /* msg */
            invokespecial java.lang.Error.<init>:(Ljava/lang/String;)V
         1: .line 340
            aload 0 /* this */
            aload 2 /* x */
            putfield javax.xml.datatype.FactoryFinder$ConfigurationError.exception:Ljava/lang/Exception;
         2: .line 341
            return
        end local 2 // java.lang.Exception x
        end local 1 // java.lang.String msg
        end local 0 // javax.xml.datatype.FactoryFinder$ConfigurationError this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    3     0  this  Ljavax/xml/datatype/FactoryFinder$ConfigurationError;
            0    3     1   msg  Ljava/lang/String;
            0    3     2     x  Ljava/lang/Exception;
    MethodParameters:
      Name  Flags
      msg   
      x     

  java.lang.Exception getException();
    descriptor: ()Ljava/lang/Exception;
    flags: (0x0000) 
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // javax.xml.datatype.FactoryFinder$ConfigurationError this
         0: .line 349
            aload 0 /* this */
            getfield javax.xml.datatype.FactoryFinder$ConfigurationError.exception:Ljava/lang/Exception;
            areturn
        end local 0 // javax.xml.datatype.FactoryFinder$ConfigurationError this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Ljavax/xml/datatype/FactoryFinder$ConfigurationError;
}
SourceFile: "FactoryFinder.java"
NestHost: javax.xml.datatype.FactoryFinder
InnerClasses:
  ConfigurationError = javax.xml.datatype.FactoryFinder$ConfigurationError of javax.xml.datatype.FactoryFinder