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Wrapper classes

 
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Wrapper classses are not mentioned in the scjp objectives.Will they come in the exam?
And also tell me what is this JLS and where can I find it
 
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Originally posted by Gautam Sewani:
And also tell me what is this JLS and where can I find it


http://java.sun.com/docs/books/jls/second_edition/html/j.title.doc.html
 
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JLS - The Java Language Specification
Offhand, I don't recall if knowledge of the wrapper classes are required - but it can be very useful to know how to use them.
While Sun's Java Tutorial doesn't seem to cover this topic with much detail or examples, it does at least cover it in part of The Numbers Trail.
The main point to realize (in my opinion) is the wrapper classes provide the programmer with an easy way to treat a primitive data type value as a regular old object. These classes also provide a few useful static methods.
Good Luck.
[ April 20, 2002: Message edited by: Dirk Schreckmann ]
 
Greenhorn
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Questions involving wrapper classes did appear on my exam about 10 days ago. Key points to remember are that wrapper objects are immutable and their toString() method allows concatenation with other strings. For example,
Integer someNum = new Integer(15);
System.out.println("Number is " + someNum);
will display "Number is 15".
They are also handy for string <-> primitive conversion, displaying the hexadecimal string for an integer, etc..
 
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Question related wrapper class do come.....
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