You cannot download  JDK directly from Sun because of our country (Iran).
Use a proxy server to dowload it.

It's most likely because your IP address shows that you're attempting the download  from Iran. Iranian users are banned from the download section as part of the US sanctions. Try to find and download the jdk from elsewhere, like downloads.com.

You can download  it from https://olex.openlogic.com/packages/jdk?show=versions&version=2880

try this proxy server !!!.
http://webonweels.com/cgi-bin/index.cgi/000010A/
this is jdk download  link from http://download.java.net/
http://webonweels.com/cgi-bin/index.cgi/000010A/http/download.java.net/jdk6/binaries/

I downloaded jdk6 from https://olex.openlogic.com/packages/jdk?show=versions&version=2880
but when I want to execute jdk-6u16-windows-x64.exe it shows a message:
"jdk-6u16-windows-x64.exe is not a valid win32 application."
and when I want to execute jdk-6u16-windows-i586.exe it shows a message:
"the windows  installer service  could not be accessed. this can occur if you are running
windows in safe mode,or if the windows installer is not correctly installed.contact your
support personnel for assistance."

In addition to what Khosro says, make sure you have downloaded the entire file. The "XYZ is not a valid win32 application" usually indicates that you have downloaded a corrupt package and it's incomplete. Try to verify the final result using a hash or something like that or make sure what you downloaded matches the file size-wise. If you're downloading  something behind a proxy, it's been my experience that sometimes packets are dropped and what you get is not always what you expected.

I installed windows  Installer from the first link
and I don't have a filter and I downloaded jdk-6u16-windows- i586.exe again
from https://olex. openlogic. com/packages/ jdk?show= versions&version=2880
, again the same error: "the windows installer service  could not be accessed. this can occur if you are running windows in safe mode,or if the windows installer is not correctly installed.contact your
support personnel for assistance." but my windows is not in a safe mode.
how can I have proxy server to download  it.