Java and unchecked warnings

I've written a simple Java program to read through a web page and extract pronouns. The strings that hold the pronouns are added to a collection, and I've been puzzled about an error message the javac compiler keeps returning about unchecked or unsafe operations, and the recommendation to compile with the -Xlint:unchecked operation. Eventually, I found this page (at angelikalanger.com) which explains what it all means.

Spent this morning rebuilding my linux server's software setup. A couple of weeks ago, I bought a second hard drive for the machine from eBay, and installed it - the first time I ever set foot in the internals of a computer! Actually putting the drive into the box was hard enough - it's a 1U server, so the overhead space is really limited, and the IDE cables were getting a little contorted. But when it came to booting again, I kept getting a "PXE-E53 No bootfile found" during pre-boot. There's precious little information about this PXE (Pre-boot Execution Environment) available on the web, but eventually I found out that the cause is probably in the boot sequence - the order of the devices the PC boots from. And lo! The machine was trying to boot from HDD1, whereas the disk that had the MBR (Master Boot Record) was now HDD0. One quick BOIS change later, order was restored. But this was after 3 days of hair-pulling, and several linux re-installs (in clueless desparation!!) - hence the need to reinstall all my libraries and software: tomcat, jakarta-oro, lucence, etc.