code: private String defaultPrimitiveValue(Class<?> clazz){
  		
  		return clazz == byte.class  || 
  			   clazz == short.class || 
  			   clazz == int.class? "0":
  			   clazz == long.class? "0L":
  			   clazz == float.class? "0.0f":
  			   clazz == double.class? "0.0d":
  			   clazz == char.class ? "'\u0000'":
  			   clazz == boolean.class ? "false":
  			   "null";
  					   
  	}
docs: Returns the default values of primitive types in the form of strings.
  @param clazz primitive type
  @return a string that contains default value