Why BeanUtils.copyProperties throw IllegalArgument Exception?

Question

I have two classes with the same attributes and the same get and set methods, one follows the DTO pattern and a VO pattern.

So I have something like this:

classDTO
    private String x;
    private String y;

classVO
    private String x;
    private String y;

Why is the following code throwing the exception illegalArgumentException?

BeanUtils.copyProperties(classVO, classDTO);

Who knows? We can't see the stack trace or what the actual class definitions are. — Dave Newton, Oct 19 '17 at 11:50
Yeah, I know what it is. *Your* classes. You *say* what they are, but you don't *show* what they are, nor the complete stack trace. — Dave Newton, Oct 19 '17 at 12:49
My classes are just 2 class with the same properties and all attribute are string, like my example. And i receive illegalargumentException — resla95, Oct 19 '17 at 12:59

score 0 · Accepted Answer · answered Oct 19 '17 at 16:23

Read the API and you get the answer to your question:

https://commons.apache.org/proper/commons-beanutils/javadocs/v1.9.3/apidocs/org/apache/commons/beanutils/BeanUtils.html

Throws:

IllegalArgumentException - if the dest or orig argument is null or if the dest property type is different from the source type and the relevant converter has not been registered.

Also, the Java definition of a bean is a serializable class with a default constructor and getters and setters that allow access to its fields. Your example classes don't fulfill those requirements.

Why BeanUtils.copyProperties throw IllegalArgument Exception?

1 Answers1