Hello

Could you pls tell me what is memory leaking and Why does it occurs.?

Suppose that I have a servlet application that send mail with attachment.

The program contains 2 clasees.



1. index.class- a servlet that accepts "email" from user


2. Mail.class- a servlet that do mailing function.





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let us examine how this work


The user input email using index.class. After validating the user request the

index.class calls "sendmail method" of Mail.class .



The sendmail method connects to database and fetches some data and stores in
a ByteArrayOutputStream.

The program attach this content to mail and send to the email address.



When the program calls the sendmail method a new object of ByteArrayOutputStream
is created with every request.



eg


public void sendMail()

{

ByteArrayOutputStream stream= new ByteArrayOutputStream();

}




The amount of data that will be stored in ByteArrayOutputStream will be about 1 mb.

so if there are 10 request; 10 ByteArrayOutputStream instances are created.


After the program finishes the grarbage collector collects the unused objects and frees the memory



But consider grarbage collector only work when the server is idle.If the above class is
frequenty used the the memory will be filled with unused objects[instances of ByteArrayOutputStream with a mimmuk data of 1 mb]




Could you pls tell me how can I handle such situation? By assigning a null value to the

ByteArrayOutputStream instance will help to free the memory?



if a code change will help?if so pls help me to do the change.


Also how can I detect that there is a "memory leaking" in the program.

Is it possible to find what object causes the problem?




Thanks in advance


sabu