Oracle's newly released Java 7 runtime is relatively painless to install and uninstall.

Java’s shady bundled adware is no longer a Windows exclusive, as Oracle has started sneaking the Ask.com toolbar into the Mac version. Similar to the Windows version, Java for OS X now attempts ...

You can check which Java version is on your Mac to see if you have the most up-to-date Java running, or you can check on the Java website.