Difference between request.getSession() and request.getSession(true)

Question

I understand the difference between request.getSession(true) and request.getSession(false). But request.getSession() & request.getSession(true) look very similar!

Both "return the current session associated with this request", but differ in:

request.getSession():

"or if the request does not have a session, creates one"

request.getSession(true):

"if there is no current session, returns a new session"

I don't understand the difference between them, is it that (if none exists) they create a new session but the first one doesn't return it but the second one does?

Source: http://docs.oracle.com/javaee/6/api/javax/servlet/http/HttpServletRequest.html

Edit:

Someone tagged/marked my question as duplicate even though it isn't. I will explain why.

I have explicitly asked for the difference between request.getSession() & request.getSession(true) and NOT between request.getSession(true) & request.getSession(false)! I have stated , again explicitly, that I already understand the difference b/w ..(true) & ..(false).

The question linked as a possible duplicated of of asks about the difference b/w ..(true) & ..(false) and not ..(true) & ..()

Solution 1

request.getSession() is just a convenience method. It does exactly the same as request.getSession(true).

Solution 2

request.getSession() will return a current session. if current session does not exist, then it will create a new one.

request.getSession(true) will return current session. If current session does not exist, then it will create a new session.

So basically there is not difference between both method.

request.getSession(false) will return current session if current session exists. If not, it will not create a new session.

Solution 3

Method with boolean argument :

  request.getSession(true);

returns new session, if the session is not associated with the request

  request.getSession(false);

returns null, if the session is not associated with the request.

Method without boolean argument :

  request.getSession();

returns new session, if the session is not associated with the request and returns the existing session, if the session is associated with the request.It won't return null.

Solution 4

They both return the same thing, as noted in the documentation you linked; an HttpSession object.

You can also look at a concrete implementation (e.g. Tomcat) and see what it's actually doing: Request.java class. In this case, basically they both call:

Session session = doGetSession(true);

Solution 5

request.getSession(true) and request.getSession() both do the same thing, but if we use request.getSession(false) it will return null if session object not created yet.

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Comments

[Arun]

This will create a new session if the current session is null and we don't want that. If current session is null, log him out instantly.

[deadend]

Above answer is easy to understand. Thanks!