Description Compl Yue Still 2005-12-15 10:54:16 EST

*---
In other words, it is permissible to omit the curly braces when a single-element array is to
be associated with an array-valued annotation type element.
*---
Above is from JLS3.0

But I found if JDT apt env, when an annotation has an array type element, and used with a single-element array but without the optional curly barces, call to get the element value will return a non-array value, and finally caused a runtime ClassCastException.

That's to say, if we have one annotation defined like this:

public @DemoAnno
{
  String[] value();
}

And used it like:

@DemoAnno("whatever")

And we try the following when processing it:

DemoAnno da = Declaration.getAnnotation(DemoAnno.class);
String[] dav = da.value(); // here it returns the String rather than the String array.

And this will finally cause an unchecked ClassCastException.