“Field Summary” on java api doc

Question

when I read the API documentation of Java I see a field with the name "Field Summary". What this Part is used for?.

What is the use of the constant and classes in this field?.

thanks.

Answer 1

The “Field Summary” of a generated Javadoc page is for summarizing the (typically public and protected) fields of a class, and providing links to the more detailed descriptions of the fields further down the page. Just as with methods, the text in the summary section for fields consists of the first sentence from the associated detail section.

Since good practice has evolved for Java that means that mutable fields are usually private, it is usually just constants that are documented there (e.g., java.lang.Double has a few) though there are some classes that have modifiable fields (e.g., javax.xml.ws.Holder has one, and the class is sufficiently simple that this isn't a problem).