C# to Java: What is a [DefaultProperty("value")]?

Question

I do not understand how the DefaultProperty Metadata tag work or what it signifies. I've read the MSDN and went through the sample but I find it confusing.

DefaultPropertyAttribute Class

I've read a few blogs and they seem to refer to the indexers. I'm not sure why you would want metadata for your properties? I am coming from a Java background, perhaps a Java analogy would help.

[DefaultProperty("Value")]
    public abstract class FOO<T> : ANY, IBAR<T>
    {
        public FOO() { }
        public FOO(T value) { this.Value = value; }
        public virtual T Value { get; set; }
    }

Follow up: Property Grid

Answer 1

This is used for property grids.

When you select a component in the designer, it looks for a DefaultProperty attribute and selects that property by default.

You can safely ignore it.

The DefaultEvent attribute is similar.

Answer 2

Attributes are metadata, like the Java annotations. They're not used by the class to which they are applied, but by other classes, or the IDE designer for example.