Dennis.

Java, Spring, C# and Python: hands-on explanations, backed by 11 years of industry experience.

„You understand programming when you know why a solution works. My goal: that you don't copy code, but get it working yourself."

Free intro with Dennis →

industry experience: 11 y
Java Engineer: Senior
since 2015: FIAE

ABOUT DENNIS

What Dennis brings, and why it matters for your code.

I help university students, apprentices and career changers truly understand programming: hands-on, structured and clear.

My path started in 2015 with an apprenticeship as a software developer (Fachinformatiker Anwendungsentwicklung). Since then I have gathered more than 11 years of software development experience and shipped real applications across two industry roles. That lets me combine solid technical knowledge with genuine industry practice.

My focus areas are Java, Spring, C#, Python, OOP, algorithms, data structures and unit testing. In sessions I explain complex topics step by step, surface the typical thinking traps and develop clean, traceable solutions with you.

Exam preparation, support during an apprenticeship, a first entry into programming or help with projects: my goal is that you understand the solution, not just know it.

Career and stations.

Real, hands-on experience from production projects.

Today · WORK

Senior Java Software Engineer

Industry
- Java and Spring in a production backend: REST APIs, persistence, tests, deploys.
- Code reviews and mentoring of junior developers.
- C#/.NET and Python stacks in use as projects require.
2015 to today · WORK

Software development in industry

2 roles, 11 years combined
- Java, Spring, C# and Python applied in real product teams.
- Focus: OOP, algorithms, data structures and unit testing.
- Production responsibility from the first method to deployment.
2015 to 2018 · EDUCATION

Apprenticeship: Fachinformatiker Anwendungsentwicklung (application development)

Company training · IHK final exam
- Three years of working life plus vocational school: code that has to run, not just code for a grade.
- The IHK project and technical exam, from first-hand experience.

EXPERTISE

Where Dennis is genuinely strong.

Only topics that Dennis actively teaches. What is not listed is not in the repertoire. We prefer to set limits over hand-waving.

Java

Variables, types, flow control
Methods, classes, scope
Collections and generics

OOP and Design

Classes, inheritance, interfaces
Polymorphism and equals/hashCode
Composition over inheritance

Spring

REST APIs with Spring MVC
JPA and Hibernate
Security and JWT

Algorithms and Data Structures

Lists, trees, hash structures
Sorting and searching
Understanding complexity (Big-O)

C# / .NET

Language comparison with Java
ASP.NET Core basics
LINQ and collections

Python

Clean scripting style
Data structures and functions
The standard library in daily work

Unit Testing

JUnit 5 must-have setup
Using Mockito where it pays off
Integration vs. unit tests

HOW DENNIS TEACHES

Three principles, every session.

Explain clearly instead of just showing solutions

Complex topics like OOP, algorithms, data structures or frameworks go step by step. Clear examples, traceable derivations, direct reference to your task.

Active problem-solving instead of passive listening

I guide you through tasks, ask the right questions and help you develop your own solution paths. That is how you learn to analyse problems yourself and solve them cleanly.

Solid foundations before complexity

Before new topics build on top, object orientation, control structures, data structures and debugging must really sit. Stable foundation first, more demanding tasks after.

AVAILABILITY · NEXT MONTH

Click a slot, book it.

All times in Europe/Berlin. Pick a slot for a 1:1 session; you choose the topic in the next step.

Different time in mind? Write to us , we will try to find a slot.

Ready to book Dennis?

Free intro call, 30 minutes, in the browser. You decide what comes after.

Book free intro with Dennis See all tutors