Redhat Jboss Fuse is open source enterprise ESB which is enterprise adoption of Apache servicemix.
Redhat Jboss Fuse is also known as just Fuse ESB,Jboss Fuse or just Fuse.
An ESB is standard based integration platform that combines messaging, web services, data transformation and intelligent routing to reliably connect and coordinate integration of significant number of diverse application across extended enterprises with transaction integrity
–David Chappell, ESB Theory in practice.
Redhat tries to give all above features with not single technology but as platform which is mix of various technologies. This platform is known as Fuse.
Fuse provides the ESB functionalities with the help of below technologies
Apache camel is lightweight java library for implementing various EIPs. EIP stands for Enterprise Integration Pattern.EIP is nothing but standard way of integrating two or more disperate systems.EIP is pattern identified for integration.
For example its very common problem that we have one system which we want to communicate with other three systems. So this is very well known problem in integration , we solve this problem with EIP known as Multicast which is pattern for sending message from one input system to multiple system.
Like multicast camel supports multiple pattern for solving various problems in integration.
Apache CXF is also a java library for writting Webservices.
Apache karaf is OSGi based container in which our components developed with camel or cxf work together to solve our integration platform.
This is how Fuse manages to give us solution to our all integration problems and provides ESB functionalities.