Java Log Viewer

Just wanted to say that I've finally found a tool that I can get along with just fine...

It's called LogExpert (see http://www.log-expert.de/) and is free. Besides the usual tail function, it also has a filter and a search function - two crucial things that are missing from BareTail. And if you happen to want to customize the way it parses columns further, it's dead simple. Just implement an interface in .NET and you're done (and I'm a Java/Flex programmer...)

You didn't mention an OS, so I'll mention this though it is only on Windows.

Bare Metal Software makes a product called BareTail that has a nice interface and works well. They have a free version with a startup nag screen, a licensed version with no nag, and a pro version with additional features. It has configurable highlighting based on matching lines against keywords.

They also have a BareGrep product too, which provides similar grep capabilities. Both are excellent and very stable and better than anything I've seen on Windows. I liked them so much I bought the bundle with both pro versions for $50.

I'm using OtrosLogViewer. You can mark log events manually or using string/regular expression. You can filter events based on level, time thread, string or regular expression. Logs can be imported by listening on socket or connecting to Log4j SocketHubAppender

You can take a look at Youtube video or screenshots:

Disclaimer: I am the author of OtrosLogViewer

I am using Notepad++ with my custom log file highlighting UDL. Looks like this: