October 30, 2018 Product Developers Urban Malc
KumuluzEE Fault Tolerance Circuit Breaker Retry Bulkhead Timeout Fallback Microprofile Fault Tolerance

KumuluzEE Fault Tolerance 1.0.1 released

We are happy to announce the release of KumuluzEE Fault Tolerance 1.0.1. This release brings improved compatibility with the MicroProfile specification.

KumuluzEE Fault Tolerance is now integrated with MicroProfile Config, which enables greater flexibility when configuring fault tolerance mechanisms. Check out the MicroProfile specification to learn about various ways to influence fault tolerance behavior directly from the configuration files (or other configuration sources).

We have also added another implementation of Circuit Breaker alongside existing Hystrix implementation. The main feature of our implementation is the support for the successThreshold parameter and full compatibility with the MicroProfile specification.

From the README:

The default value (HYSTRIX) uses the Hystrix implementation of circuit breaker, which does not support the successThreshold parameter. It can also violate the failureRatio parameter, since it updates error percentage on a regular interval (configurable with metrics.health-interval) and not on every invocation. The alternative implementation (SUCCESS_THRESHOLD) supports the successThreshold parameter and always respects the failureRatio parameter since it calculates the error percentage before every invocation. However, this calculation can be inefficient in high throughput applications. We recommend the usage of the default value HYSTRIX implementation, since it offers higher scalability. The drawbacks of HYSTRIX implementation can be easily mitigated by properly tuning the configuration.

The parameters of annotations are now validated on application startup. This enables easier debugging and prevents hard to notice bugs.

Another important addition in this release is the inclusion of MicroProfile TCK, which verifies our compatibility with the MicroProfile specification.

Note that this is a patch release even though the release contains new features. We are breaking the semantic versioning scheme in this case because we want to keep the version aligned with the MicroProfile FT specification version.


  • Integration with MicroProfile Config.
  • Added CB implementation which honors the successThreshold parameter.


  • Added Microprofile TCK.
  • Added validation of annotation parameters on startup.

More details about this release can be found on GitHub.

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