Program: 44136
Project: 44136
Buggy source:
private Handler configureHandler(final Properties properties,final String handlerName) throws IOException {
  if (configuredHandlers.containsKey(handlerName)) {
    return configuredHandlers.get(handlerName);
  }
  final String handlerClassName=getStringProperty(properties,getKey("String_Node_Str",handlerName));
  if (handlerClassName == null) {
    throw new IllegalArgumentException("String_Node_Str" + handlerName + "String_Node_Str");
  }
  final Handler handler;
  try {
    handler=(Handler)Class.forName(handlerClassName).getConstructor().newInstance();
  }
 catch (  Exception e) {
    throw new IllegalArgumentException("String_Node_Str" + handlerName + "String_Node_Str",e);
  }
  configuredHandlers.put(handlerName,handler);
  final String levelName=getStringProperty(properties,getKey("String_Node_Str",handlerName,"String_Node_Str"));
  if (levelName != null) {
    handler.setLevel(LogContext.getSystemLogContext().getLevelForName(levelName));
  }
  final String encodingName=getStringProperty(properties,getKey("String_Node_Str",handlerName,"String_Node_Str"));
  if (encodingName != null) {
    handler.setEncoding(encodingName);
  }
  final String errorManagerName=getStringProperty(properties,getKey("String_Node_Str",handlerName,"String_Node_Str"));
  if (errorManagerName != null) {
    handler.setErrorManager(configureErrorManager(properties,errorManagerName));
  }
  final String filterName=getStringProperty(properties,getKey("String_Node_Str",handlerName,"String_Node_Str"));
  if (filterName != null) {
    handler.setFilter(configureFilter(properties,filterName));
  }
  final String formatterName=getStringProperty(properties,getKey("String_Node_Str",handlerName,"String_Node_Str"));
  if (formatterName != null) {
    handler.setFormatter(configureFormatter(properties,formatterName));
  }
  configureProperties(properties,handler,getKey("String_Node_Str",handlerName));
  return handler;
}

Fixed version (ground truth):
private Handler configureHandler(final Properties properties,final String handlerName) throws IOException {
  if (configuredHandlers.containsKey(handlerName)) {
    return configuredHandlers.get(handlerName);
  }
  final String handlerClassName=getStringProperty(properties,getKey("String_Node_Str",handlerName));
  if (handlerClassName == null) {
    throw new IllegalArgumentException("String_Node_Str" + handlerName + "String_Node_Str");
  }
  final Handler handler;
  try {
    handler=(Handler)Class.forName(handlerClassName).getConstructor().newInstance();
  }
 catch (  Exception e) {
    throw new IllegalArgumentException("String_Node_Str" + handlerName + "String_Node_Str",e);
  }
  configuredHandlers.put(handlerName,handler);
  final String levelName=getStringProperty(properties,getKey("String_Node_Str",handlerName,"String_Node_Str"));
  if (levelName != null) {
    try {
      handler.setLevel(LogContext.getSystemLogContext().getLevelForName(levelName));
    }
 catch (    IllegalArgumentException e) {
      System.err.printf("String_Node_Str",levelName,handler,e.getMessage());
    }
  }
  final String encodingName=getStringProperty(properties,getKey("String_Node_Str",handlerName,"String_Node_Str"));
  if (encodingName != null) {
    try {
      handler.setEncoding(encodingName);
    }
 catch (    UnsupportedEncodingException e) {
      System.err.printf("String_Node_Str",encodingName,handler,e.getMessage());
    }
  }
  final String errorManagerName=getStringProperty(properties,getKey("String_Node_Str",handlerName,"String_Node_Str"));
  if (errorManagerName != null) {
    try {
      handler.setErrorManager(configureErrorManager(properties,errorManagerName));
    }
 catch (    IllegalArgumentException e) {
      System.err.printf("String_Node_Str",errorManagerName,handler,e.getMessage());
    }
  }
  final String filterName=getStringProperty(properties,getKey("String_Node_Str",handlerName,"String_Node_Str"));
  if (filterName != null) {
    try {
      handler.setFilter(configureFilter(properties,filterName));
    }
 catch (    IllegalArgumentException e) {
      System.err.printf("String_Node_Str",filterName,handler,e.getMessage());
    }
  }
  final String formatterName=getStringProperty(properties,getKey("String_Node_Str",handlerName,"String_Node_Str"));
  if (formatterName != null) {
    try {
      handler.setFormatter(configureFormatter(properties,formatterName));
    }
 catch (    IllegalArgumentException e) {
      System.err.printf("String_Node_Str",filterName,handler,e.getMessage());
    }
  }
  configureProperties(properties,handler,getKey("String_Node_Str",handlerName));
  return handler;
}