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Hashtable

 
Angela D'souza
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what Hashtable class is for in java?
I look in API, but I still have confusion
Thanks,
Angela
 
Shivaji Marathe
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Think of a hashtable as a special kind of database table with two columns. When you create the table, you don't have to specify the data types of these columns. The first column is the ID or Key column, the second is the actual object ( or rest of the record, if you will ).
Just like you can do a Select * where ID = XX in an Relational database table, you can do a get() on a hastable. You pass the ID value to the get method. It returns an Object which you can then cast to the real type of the object.
You can look at the methods such as
values (), keyset(), entryset() and put() roughly along the following lines.
values() - return the second column from all the rows of the table
keyset() return the ID column from all the rows of the table
entryset() return both the columns from all the rows
put() insert a record with the given values for the two columns and so on.
Remember this is just an anology to help you understand how hashtable can be used.
HTH
 
Angela D'souza
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Thanks a lot Shivaji,
 
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