The monitoring output can be persistently saved into logs, e.g.,

• file system (async/sync)
• database (async/sync)

or directly processed via streams using a custom or standard message protocol, e.g.,

• TCP (sync)
• JMS and JMX queues (async), with current support for
  • ActiveMQ
  • HornetQ
  • OpenJMS
• AMQP writer and reader, with current support for
  • RabbitMQ

Kieker provides several predefined and customizable probes to instrument and monitor your target application.
For example, there are probes which collect

• the execution times of method invocations including their fully qualified name
• the behavior of different threads
• resource information, such as the CPU utilization and the memory footprint

Furthermore, it is easily possible to define custom probes, especially based on predefined probes.
For this purpose, Kieker offers a user-friendly domain specific language called the Record Instrumentation Language (see the tab “Tool Integration”).

Kieker offers multiple ways of instrumentation for control flow tracing, e.g.,

• Manual source code insertion
• Automatic source code insertion via Aspect-Oriented Programming (AOP), e.g.
• AspectJ. The insertion points can be defined
  • by annotations in the source code or via
  • pointcuts in an external configuration file (aop.xml) for better seperation of concerns.
• Middleware interception, e.g., Spring
• Servlet
• CXF/SOAP

and resource monitoring, e.g.,

• Sigar or Servlet to monitor
  • CPU utilization
  • Memory usage