Jonathan Halliday
Software Engineer at IBM
Summary
🤩
RockstarJonathan Halliday is a seasoned Java middleware engineer with 14 years of experience building and optimizing back-end systems, particularly for distributed and persistence layers. He has contributed substantial open-source work to high-profile projects such as Hibernate OGM (Cassandra backend) and OpenTelemetry Java, implementing core type mapping, association handling, and profiling data models. His contributions to Narayana show a practical focus on transaction management performance, threading, and durable SlotStore backends, reflecting deep expertise in reliability and low-level system optimization. Jonathan combines hands-on coding with an eye for pragmatic refactoring and compatibility (e.g., Cassandra 2.2 support), making him effective at evolving legacy and emerging infrastructure. Colleagues would describe him as detail-oriented, performance-minded, and comfortable navigating complex consistency and serialization challenges.
15 years of coding experience
Github Skills (22)
transaction10
back-end-development10
cassandra10
data-modeling10
java10
javas10
transactionscope10
hibernate10
performance-optimization10
profiling10
opentelemetry10
cql10
transaction-manager10
concurrency10
admin9
Programming languages (11)
Github contributions (5)
open-telemetry/opentelemetry-java
May 2022 - Apr 2026
OpenTelemetry Java SDK
Role in this project:
Back-end Developer
Back-end DeveloperContributions:46 reviews, 10 PRs, 60 comments in 3 years 11 months
Contributions summary:Jonathan primarily contributed to the development of the OpenTelemetry Java SDK, focusing on adding exporter data classes and implementing data models for profiling signals. This involved creating and modifying Java files related to profiles, including classes for data structures like `ProfileContainerData`, `ProfileData`, and `SampleData`. Their work extended to marshaling and unmarshaling data, along with tests, indicating a focus on the profiling instrumentation aspect of the SDK.
open-telemetry-javaopentelemetry
jbosstm/narayana
Feb 2018 - Apr 2021
The codebase for the narayana project
Role in this project:Back-end Developer
Back-end DeveloperContributions:12 reviews, 27 commits, 16 PRs in 3 years 3 months
Contributions summary:Jonathan primarily contributed to performance improvements and bug fixes within the Narayana project, focusing on the core transaction management logic. Their work involved optimizing thread utilization and string serialization, enhancing the efficiency of the system. They also implemented and refactored the SlotStore backend, including disk and persistent memory implementations. These changes demonstrate a strong understanding of the project's internal workings and a focus on improving its performance and reliability.
deep-learningcodebasepythonmachine-learning
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