code: public Map<String,Object> addConfigProperty(Map<String,Object> properties, String key, String defaultValue)
      {
      	if (this.getProperty(key) != null)
      		properties.put(key, this.getProperty(key));
      	else if (defaultValue != null)
      		properties.put(key, defaultValue);
      	return properties;
      }
docs: Add this property if it exists in the OSGi config file.
  @param properties
  @param key
  @param defaultValue
  @return