Pantelis Zarakis
Issunexa issue and service management synthetic demo interface

Java Backend / Full-Stack Developer

PantelisZarakis

Between code and creation.

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Issunexa

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Synthetic demo data
Agent workspace
Authentic Issunexa agent view with a synthetic ticket, status, priority and description.
Open live demo
Issunexa demo entry screen captured from the actual application.
Issunexa logo

From request
to resolution.

A full-stack ticket management application. Requesters track tickets; agents claim work, update status and reply.

Java 21 / Spring Boot / React / TypeScript / PostgreSQL / Flyway

Live demo Source code
Free hosting may need a moment to wake up. Synthetic demo data only.

Engineering decisions

Transactional updates

Ticket creation, claims and status changes commit atomically with their history entries.

Read the service
Access control

Backend authorization enforces requester ownership, staff roles and isolated demo workspaces.

Inspect access rules
Testing

Backend, frontend and real-stack browser tests cover the application.

View the CI run

What I've
built.

IssunexaFull-stack applicationWarexisDistributed systemni_GHT_siLinux system monitor

Warexis

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Service architecture

Scroll or select a step
OrderPlacedReservation resultOrderConfirmed
Apache Kafka
Service focus

Order owns its PostgreSQL database and transactional outbox. It publishes OrderPlaced and, after reservation, OrderConfirmed.

01 / 03

Order publishes OrderPlaced through Kafka. Inventory consumes the event to begin its stock reservation.

Simplified confirmation flow. Each service owns its database. Step 3 follows a successful reservation.

Warexis logo

From order
to fulfillment.

Three Java services coordinate stock reservations and fulfillment plans through Kafka. Each service owns its PostgreSQL database.

Java 21 / Spring Boot / Kafka / PostgreSQL / Keycloak / Docker

Explore the architecture
Local Docker environment. No hosted demo.

Engineering decisions

Transactional outbox

Domain changes and outbox records commit together. Relays publish to Kafka with at-least-once delivery.

Read the decision
Idempotency and retries

Durable deduplication prevents duplicate effects. Bounded retries and dead-letter handling support deliberate failure recovery.

Inspect failure tests
Cross-service verification

Tests exercise all three packaged services with real Kafka, PostgreSQL and Keycloak.

View the CI run

Experimental Linux System Monitor

ni_GHT_si

Built in C++20 and Qt6/QML, with background sampling, process inspection and optional NVIDIA telemetry.

Development Discontinued

Release v0.1.0 Source
Authentic ni_GHT_si overview showing CPU, memory, load and per-core telemetry in its dark Qt interface.
Engineering notes & release verification

Engineering decisions

Background sampling

Independent sampling workers publish telemetry snapshots. Bounded history and adjustable sampling profiles control retained data and cadence.

Inspect the sampling engine
Process safety

Process control retains a pidfd and checks the target before signaling. Unsupported or ambiguous targets remain protected.

Read the pidfd implementation
Release verification

The v0.1.0 release records 27 CTest cases and seven targeted sanitizer cases. Performance targets and long-soak reliability remain unestablished.

Read release verification

About
me.

I’m an engineering student focused on Java backend and full-stack development. My projects explore application architecture, testing and distributed systems.

Applications

Java
Spring Boot
PostgreSQL

Interfaces

React
TypeScript
HTML & CSS

Systems & tools

Kafka & Docker
Linux
JUnit & CI

2023–2028

Engineering studies

Computer, Informatics & Telecommunications Engineering
International Hellenic University
Studies in progress

2018–present

Websites &
digital production

WordPress administration at Autokollises.gr.
Graphic design and digital production support at Zarakis.gr.

Language & learning

English & technical coursework

English / Cambridge C2 Proficiency (CPE).
Cisco networking and cybersecurity coursework.

Open-source
contributions.

Merged #1198

Higher-Kinded-J

Actionable compiler diagnosticsMerged #22100

Checkstyle

Regression fixtures & suppression cleanup

Open to junior Java backend and full-stack opportunities.

Get in
touch.

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