what is proxy server,what is Browser Cache in java 2011

[saneha]

need information
sir i have need information about:

1- what is proxy server?

2-what is Browser Cache?

3-what is sever log and why we maintain it?

[Vuhelper]

Proxy Server
In computer networks, a proxy server is a server (a computer system or an application program) that acts as an intermediary for requests from clients seeking resources from other servers. A client connects to the proxy server, requesting some service, such as a file, connection, web page, or other resource, available from a different server. The proxy server evaluates the request according to its filtering rules. For example, it may filter traffic by IP address or protocol. Web Proxy Servers are most popular proxy servers.
Browser Cache
Your browser (Firefox, Internet Explorer, etc) has a folder in which certain items that have been downloaded are stored for future access. Graphic images (such as buttons, banners, icons, advertising, graphs, and color bars), photographs, and even entire web pages are examples of cache items. When going to a page on a website, your computer will check its cache folder first to see if it already has those images and, if so, it won't take the time to download them again. This makes for a faster loading of the page
Sever Log
A Server log is a log file (or several files) automatically created and maintained by a server of activity performed by it. A typical example is a web server log which maintains a history of page requests.