mail api set from address wrongly in java

I am using mailapi.jar to sene mail.i am using gmail smtp details.i am setting authentication for that session.

i also setting from address in setfrom() method. i can receive mail..but that from address was wrong .

for Example. I am setting from address like from@gmail.com To address like to@gmail.com

i can receive the mail in to@gmail.com id. But the from address is my authentication id.not the from@gm开发者_C百科ail.com

that may be enforced by the mail server. decent mail servers don't generally let you impersonate anyone you like.