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What are First Class Objects?

 
Ranch Hand
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I have come across this statement "First Class Objects" but was not able to infer what it exactly means.

can somebody explain please.

Thanks
 
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Quoted from JavaWorld.com (reference below)...

"Instances of the PersistenceCapable classes that have JDO identity represent first-class objects; these objects are stored in a data store with their associated second-class objects (if any) and primitive values...

"Also PersistenceCapable instances, second-class objects differ from first-class objects in that they have no JDO identity of their own..."

("A JDO instance is a Java class instance that implements the application functions and represents data in an enterprise data store.")

Ref: http://www.javaworld.com/javaworld/jw-04-2002/jw-0412-jdo.html

NOTE: This appears to be beyond the scope of the SCJP 1.4 exam.
[ October 19, 2004: Message edited by: marc weber ]
 
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There is a much broader meaning for "first class object." See if THIS ARTICLE helps. It hasn't helped me much yet

Or this quote "the only entities in Java that are not objects (or arrays of objects) are the primitive types (Boolean, byte, char, short, int, long, float, and double). Everything else in Java is a "first-class" Object of some kind an instance of some class that inherits directly or indirectly from java. lang.Object." from JAVA 911.
 
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