syslog-ng is a syslogd replacement for a wide variety of UNIX systems that supports IPv6 and is capable of transferring log messages reliably using TCP and SSL and filtering the content of messages using regular expressions. Both RFC3164 and RFC5424 style messages are handled, but more esoteric formats like BSD process accounting logs are supported too. Apart from regular text files, it supports storing messages into SQL and MongoDB databases, and forward messages to local processes via pipes or UNIX domain sockets. This makes syslog-ng ideal as an integration platform. syslog-ng supports extracting structured information from the traditionally text based syslog via csv-parser(), db-parser(), and patterndb. Tag based classification, rewriting messages, and outputting messages in JSON is also possible. This makes syslog-ng ideal for preprocessing events for further analysis, be that home-grown scripts or SIEM systems. syslog-ng scales well on today's multi processor and multi-core systems: reaching 1,000,000 messages per second is a reality for the simplest use cases.
Chainsaw is a GUI log viewer and filter for the Log4J package. It listens for LoggingEvent objects sent using the SocketAppender and displays them in a table. The events can be filtered based on Priority, Thread name, Category name, or Message. It can also load events logged to a file.
Jukebox is a collection of reusable components that allow you to create a flexible server-side and middleware framework. It features semaphores and services (not quite your usual set), a Finite State Machine implementation based on Generics, a Datastream framework (data producers, consumers and loggers), and a JDK 1.6 compliant JMX framework based on Annotations.
vlogger is a logger daemon for Apache. It will accept piped logfile input, split it according to its corresponding virtual host (using a file cache to avoid resource limitations), and write it to disk. It automatically rotates all files and tracks them using timestamps. It is intended as a replacement for cronolog.