Apache grep big log file

I need to parse Apache log file to look for specific suspicious patterns (like SQL injections).

grep a file, but show several surrounding lines?

I would like to grep for a string, but show the preceding 5 lines and following 5 lines as well as the matched line. I'm scanning for errors in a logfile, and want to see the context.

How to send java.util.logging to log4j?

I have an existing application which does all of its logging against log4j. We use a number of other libraries that either also use log4j, or log against Commons Logging, which ends up using log4j under the covers in our environment. One of our dependencies even logs against slf4j, which also works fine since it eventually delegates to log4j as well.