Program: 12524
Project: 12524
Buggy source:
/** 
 * Convert the passed XML node into a domain object.<br> Note: this is the generic API for reading all types of UBL documents. Please refer to   {@link UBL20Reader} for a type-safe API for all supporteddocument types.
 * @param aSource The source object to be converted. May not be <code>null</code>.
 * @param aClassLoader Optional class loader to be used for JAXBContext. May be <code>null</code> to indicate to use the default class loader.
 * @param aDestClass The UBL class of the result type. May not be <code>null</code>.
 * @param aCustomEventHandler An optional custom event handler to be used in unmarshalling. May be <code>null</code>.
 * @return <code>null</code> in case conversion to the specified class failed.See the log output for details.
 */
@Nullable public static <T>T readUBLDocument(@Nonnull final Source aSource,@Nullable final ClassLoader aClassLoader,@Nonnull final Class<T> aDestClass,@Nullable final ValidationEventHandler aCustomEventHandler){
  ValueEnforcer.notNull(aSource,"String_Node_Str");
  ValueEnforcer.notNull(aDestClass,"String_Node_Str");
  final Schema aSchema=UBL20DocumentTypes.getSchemaOfImplementationClass(aDestClass,aClassLoader);
  if (aSchema == null) {
    s_aLogger.error("String_Node_Str" + aDestClass.getName());
    return null;
  }
  T ret=null;
  try {
    final Unmarshaller aUnmarshaller=createFullUnmarshaller(aDestClass,aClassLoader,aSchema,aCustomEventHandler);
    ret=aUnmarshaller.unmarshal(aSource,aDestClass).getValue();
    if (ret == null)     throw new IllegalStateException("String_Node_Str" + aDestClass.getName() + "String_Node_Str");
  }
 catch (  final UnmarshalException ex) {
    s_aLogger.error("String_Node_Str",ex);
    return null;
  }
catch (  final JAXBException ex) {
    s_aLogger.warn("String_Node_Str",ex);
    return null;
  }
  return ret;
}

Fixed version (ground truth):
/** 
 * Convert the passed XML node into a domain object.<br> Note: this is the generic API for reading all types of UBL documents. Please refer to   {@link UBL20Reader} for a type-safe API for all supporteddocument types.
 * @param aSource The source object to be converted. May not be <code>null</code>.
 * @param aClassLoader Optional class loader to be used for JAXBContext. May be <code>null</code> to indicate to use the default class loader.
 * @param aDestClass The UBL class of the result type. May not be <code>null</code>.
 * @param aCustomEventHandler An optional custom event handler to be used in unmarshalling. May be <code>null</code>.
 * @return <code>null</code> in case conversion to the specified class failed.See the log output for details.
 * @param < T > The UBL document implementation type
 */
@Nullable public static <T>T readUBLDocument(@Nonnull final Source aSource,@Nullable final ClassLoader aClassLoader,@Nonnull final Class<T> aDestClass,@Nullable final ValidationEventHandler aCustomEventHandler){
  ValueEnforcer.notNull(aSource,"String_Node_Str");
  ValueEnforcer.notNull(aDestClass,"String_Node_Str");
  final Schema aSchema=UBL20DocumentTypes.getSchemaOfImplementationClass(aDestClass,aClassLoader);
  if (aSchema == null) {
    s_aLogger.error("String_Node_Str" + aDestClass.getName());
    return null;
  }
  T ret=null;
  try {
    final Unmarshaller aUnmarshaller=createFullUnmarshaller(aDestClass,aClassLoader,aSchema,aCustomEventHandler);
    ret=aUnmarshaller.unmarshal(aSource,aDestClass).getValue();
    if (ret == null)     throw new IllegalStateException("String_Node_Str" + aDestClass.getName() + "String_Node_Str");
  }
 catch (  final UnmarshalException ex) {
    s_aLogger.error("String_Node_Str",ex);
    return null;
  }
catch (  final JAXBException ex) {
    s_aLogger.warn("String_Node_Str",ex);
    return null;
  }
  return ret;
}