Олег Veteran

CONTACT
OLEG KLYMCHUK
• Zhytomyr, Ukraine
Java Backend Developer
• [open contact info](look above in the "contact info" section)
Enterprise Infrastructure & Backend Engineering
• GitHub: https://github.com/koi1966

• LinkedIn:
EXECUTIVE PROFILE
[open contact info](look above in the "contact info" section)
More than 30 years of enterprise IT engineering. Strong infrastructure
klymchuk-171293235/
background supporting 200+ users and 300+ workstations.
CORE SKILLS Java Backend Developer with 3+ years of hands-on backend development
experience experienced with Java 17, Spring Boot, Spring Security, Spring
• Java 17
Data JPA, Hibernate, PostgreSQL, REST API, Apache POI and JavaMail.
• Spring Boot
KEY ACHIEVEMENTS
• Spring Security
• Supported enterprise IT infrastructure for 200+ users and 300+
• Spring Data JPA workstations.

• Hibernate • Provided end-to-end support, deployment, and administration of
computer hardware, peripheral devices, and network equipment, ensuring
• REST API the uninterrupted operation of organizational departments.
• JWT • Designed, deployed, and administered local area networks (LANs), while
monitoring network performance and promptly troubleshooting network
• Strong skills in SQL
issues to ensure reliable connectivity.
• PostgreSQL
• Ensured information security, protected users' personal data, and
• Sybase ASE maintained antivirus protection for workstations in compliance with
organizational security standards.
• Git
• Provided prompt technical support, troubleshooting and resolving
• Maven hardware, software, and network issues to ensure uninterrupted daily
operations.
INFRASTRUCTURE
• Designed and maintained FreeBSD-based infrastructure (DNS, routing,
• FreeBSD firewall, mail and file services).

• DNS • Developed internal Java applications used within the organization.

• Routing • Completed Sybase ASE to PostgreSQL migration.

• Firewall • Implemented automated Word/Excel report generation.

• Mail Server SELECTED PROJECTS
• File Server Internal Reporting System
• Windows Java17 | Spring Boot | Spring Security | PostgreSQL | Hibernate |
Thymeleaf | Apache POI | JavaMail
LANGUAGES
• Ukrainian Hotel Management System

• Russian Spring Boot | PostgreSQL

• English A2 Enterprise Database Search

Spring MVC | JDBC | Sybase ASE

Database Migration

Sybase ASE → PostgreSQL

PROFESSIONAL EXPERIENCE

Senior System Administrator | 1993–2024

Enterprise organization. Managed enterprise infrastructure, FreeBSD
servers, Windows workstations, networking, databases and participated in
internal software development.

Military Service (Mobilization) | 2024–2026

Returned to Java backend development after completion of service.