Максим

Bondarenko Maksim
Java Backend Developer
Poltava, Ukraine
[відкрити контакти](див. вище в блоці «контактна інформація»)
Email: [відкрити контакти](див. вище в блоці «контактна інформація»)
Telegram: https://t.me/amksme
Github: https://github.com/AgentVadim839

ABOUT ME
Java Developer with an engineering background (Linux/DevOps). Experienced
in developing fault-tolerant backend using Spring Boot, with an understanding
of transactions and multithreading. I configure infrastructure independently:
from a clean VPS to Docker containers with network security. One year of
experience in technical mentoring (Code Review, debugging).

SKILLS
●​ Java Core: Collections, Stream API, Multithreading, OOP, SOLID, CCP,
CRP, REP
●​ Spring: Spring Boot 3, Spring Security (Role-based, Filters), Spring Data
JPA, Hibernate, Spring AOP.
●​ Database: MySQL, ACID.
●​ DevOps & Infrastructure: Linux (Ubuntu headless), Bash scripting,
Docker, docker-compose, Fail2Ban, VPN tunneling.
●​ Testing: JUnit 5, Mockito.
●​ Tools & Others: Git (Advanced), Python (Automation, scripting), REST
API.
●​ English (B2)

MAIN PROJECTS
●​ Integra Bank System | Java 17, Spring Boot, MySQL, Docker |
(https://github.com/AgentVadim839/integra-bank)
○​ Transaction Security: Prevented Race Conditions and double
spending by implementing Idempotency Keys and Optimistic
Locking. This ensures balance integrity during concurrent
transactions.
○​ Security Architecture: Segregated User/Admin access via a
custom SecurityFilterChain and implemented a
UserStatusInterceptor for immediate session invalidation,
significantly enhancing system security.
 ○​ Resilience: Configured retry policies (@Retryable) for database
operations (handling version conflicts/Optimistic Locking). This
improved transaction stability and UX by eliminating the need
for manual user retries.

WORK EXPERIENCE
Technical Mentor, Remote
August 2024 – November 2025
●​ Taught 45+ students the fundamentals of algorithms and data
structures.
●​ Code Review: Analyzed student code, mentoring them on identifying
logical errors and writing clean code.
●​ Soft Skills: Developed the ability to explain complex technical
concepts in accessible language.

Backend Developer (Self-hosted Environment)
November 2024 – Present
●​ Server Administration: Administration of headless Ubuntu servers.
●​ Security Hardening: Secured the environment by implementing
Fail2Ban and configuring SSH key-based authentication to mitigate
automated brute-force attacks. These measures reduced system load
by 20%, ensured service uptime, and protected critical data.
●​ Networking: Deployed private VPN gateways integrated with DNS
filtering (AdGuard) to establish a secure network perimeter. Achieved
isolation of internal services (Database, Monitoring) from the public
network, restricting access solely to VPN tunnels and eliminating
external attack vectors.
●​ Disaster Recovery: Performed data and file system recovery following
critical failures or security incidents.

EDUCATION
Poltava University of Economics and Trade, Poltava
September 2023 – Present
Bachelor of Science in Computer Science