Graylog2 is an syslog implementation that stores logs in MongoDB. Messages are accepted via TCP or UDP. A Web interface allows you to view the log messages. It also implements GELF, the Graylog Extended Log Format, which is a simple JSON string that allows you to send long and structured syslog messages, which is very useful for customized application log monitoring.
Syslog4j provides Java components for client and server implementations of the syslog protocol (RFC 3164). UDP/IP, TCP/IP, TCP/IP over SSL/TLS, Unix Syslog, and Unix Socket Logging are supported. Advanced options are provided, including cryptographic message signatures and hashes. It is heavily tested with JUnit and Emma code coverage.
ida-syslog is a Web-based viewer for syslog data. It requires syslog data in a MySQL database. It uses AJAX and is based on jQuery and PHP. It is intended for use with rsyslog-mysql, but can be adapted to any table format via the config file. It has a fast UI with no page reloads, and can save search settings as templates for easy reuse. Tail mode and auto-loading of older entries when scrolling down. Fixes for use with Windows-Syslog-Tools (NTSyslog2, Snare).