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    • Performance

      8
      • Watch recording

        Loading a Hierarchy of Objects from PostgreSQL in a Single Query

        Let's look at different approaches to loading objects from PostgreSQL.

        • Konstantin Plotnikov

          WorkMe.io

        Room 2In RussianRUComplexity -For practicing engineers
      • Watch recording

        Is ThreadLocal Outdated? Detailed Comparison With ScopedValue

        With the appearance of virtual threads, ThreadLocal is no longer the only solution for context transfer — Java 21 introduced ScopedValue. But when to use what? Which is faster and uses less memory?

        • Alexander Matorin

          Sber

        Room 1In RussianRUComplexity -Hardcore. Really hard and demanding talk, you'll understand only if you're an experienced engineer.
      • Watch recording

        Spring AOT. Code Generation on Steroids.

        If your “hello world” Spring app needs 512 MB RAM and launches in 10 seconds, you’re not building an app — you’re running a memory leak with REST endpoints.

        • Mikhail Polivakha

          Sber

        Room 2In RussianRUComplexity -For practicing engineers
      • Watch recording

        JDK Flight Recorder in 2025

        JDK Flight Recorder is not a new technology that has undergone several rebirths in its history. The next release of JDK 25 has also not bypassed JDK Flight Recorder and brought with it new features.

        • Alexey Ragozin

        Room 2In RussianRUComplexity -For practicing engineers
      • Watch recording

        Compiling Formulas in Runtime in the Name of Performance

        How we managed to reduce CPU consumption by almost three times, and at the same time reduce the response time to user requests and the actual intensity of allocations.

        • Petr Portnov

          Ozon

        Room 2In RussianRUComplexity -Hardcore. Really hard and demanding talk, you'll understand only if you're an experienced engineer.
      • Watch recording

        Virtual Wars of the Dining Philosophers

        Using the example of a classic multithreading task, I will consider some misconceptions related to virtual threads. For this, I will use an engineering approach based on measurements.

        • Vladimir Krasilshchik

          01.tech

        Room 1In RussianRUComplexity -For practicing engineers
      • Watch recording

        Managing the Cloud Without Attracting the Users' Attention

        Let's talk about the history of degradations, how they were found and how they were fixed, and what accidents happened.

        • Aleksei Volkov

          VK

        Room 2In RussianRUComplexity -For practicing engineers
      • Watch recording

        32 GB Ought To Be Enough for Anybody

        I'll tell you how some of the old (compressed oops and compressed class pointers) and new (compact object headers) settings affect actual memory usage, and what to do if your application is approaching the 32 GB limit.

        • Oleg Estekhin

          Yandex Cloud

        Room 2In RussianRUComplexity -For practicing engineers
    • Frameworks

      7
      • Watch recording

        Loading a Hierarchy of Objects from PostgreSQL in a Single Query

        Let's look at different approaches to loading objects from PostgreSQL.

        • Konstantin Plotnikov

          WorkMe.io

        Room 2In RussianRUComplexity -For practicing engineers
      • Watch recording

        Retries: Love on the Third Try

        I will trace the path of retries from repeated attempts in real life to their implementation in microservice architectures. I'll tell you how retries have evolved in life, programming, and the Java ecosystem. Which strategies and tools help to achieve reliability, and which ones break everything.

        • Dmitrii Frolov

          T-Bank

        Room 1In RussianRUComplexity -For practicing engineers
      • Watch recording

        Spring AOT. Code Generation on Steroids.

        If your “hello world” Spring app needs 512 MB RAM and launches in 10 seconds, you’re not building an app — you’re running a memory leak with REST endpoints.

        • Mikhail Polivakha

          Sber

        Room 2In RussianRUComplexity -For practicing engineers
      • Watch recording

        From Antipattern to a Tool: The Hidden Benefits of an Open Session

        We will discuss the issue of the development with Spring in conjunction with JPA, the related performance problem, and also suggest a solution.

        • Ilya Sazonov

          Axiom JDK

        • Fedor Sazonov

          OpenIDE

        Room 1In RussianRUComplexity -For practicing engineers
      • Watch recording

        Spring Data JPA: Non-Obvious Performance Issues

        Why the service layer should return an Entity, not a DTO. Why fetching small collections can lead to million-dollar datasets. Is it worth fetching deep-nested entities. How turning off autocommit can dramatically increase application throughput.

        • Semyon Kirekov

          Avito

        Room 1In RussianRUComplexity -For practicing engineers
      • Watch recording

        OAuth 2, JWT, OIDC. Everything That Was Not Told to Us in Spring

        When it comes to OAuth 2 and working with JWT, a lot of questions arise while writing code and you have to remember a lot of nuances. The talk contains everything that Google is most often asked about. For security lovers and understanders, in one narrative using the example of Spring.

        • Pavel Kislov

          Amplicode

        Room 2In RussianRUComplexity -For practicing engineers
      • Watch recording

        Not by Spring Alone? Looking at Quarkus

        We'll look at Quarkus, Panache, gRPC and other "non-obvious" things. We will discuss where they can be useful, what kind of pitfalls are there and how to expand professional horizons.

        • Andrey Kuleshov

          Yandex Infrastructure

        Room 1In RussianRUComplexity -Introduction to technology
    • JVM

      5
      • Watch recording

        Hot JEPs 25: Anniversary

        Java 25 was released on September 16, and according to the tradition of JPoint and Joker, we will analyze all the key changes in detail.

        • Andrey Kuleshov

          Yandex Infrastructure

        • Gregory Koshelev

          Kontur

        • Vadim Tsesko

          01.tech

        Room 1In RussianRU
      • Watch recording

        Compiling Formulas in Runtime in the Name of Performance

        How we managed to reduce CPU consumption by almost three times, and at the same time reduce the response time to user requests and the actual intensity of allocations.

        • Petr Portnov

          Ozon

        Room 2In RussianRUComplexity -Hardcore. Really hard and demanding talk, you'll understand only if you're an experienced engineer.
      • Watch recording

        Virtual Wars of the Dining Philosophers

        Using the example of a classic multithreading task, I will consider some misconceptions related to virtual threads. For this, I will use an engineering approach based on measurements.

        • Vladimir Krasilshchik

          01.tech

        Room 1In RussianRUComplexity -For practicing engineers
      • Watch recording

        Java Debugging Ultimate Guide

        I will tell you about the structure and operation of the main debugging tools in JVM. I will give examples of debugging distributed applications, and also tell you about other non-trivial methods of debugging in JVM.

        • Aleksandr Tokarev

          Yandex

        Room 1In RussianRUComplexity -For practicing engineers
      • Watch recording

        32 GB Ought To Be Enough for Anybody

        I'll tell you how some of the old (compressed oops and compressed class pointers) and new (compact object headers) settings affect actual memory usage, and what to do if your application is approaching the 32 GB limit.

        • Oleg Estekhin

          Yandex Cloud

        Room 2In RussianRUComplexity -For practicing engineers
    • Kotlin

      5
      • Watch recording

        Rich Errors: Checked Exceptions in Kotlin

        Rich Errors: reinvention of Checked Exceptions. I will tell you the background of the appearance of Rich Errors, what alternatives there are in other ecosystems and why we will never have real Union types.

        • Alexander Sokolinsky

          Scientific Programming Centre

        Room 3In RussianRUComplexity -Academic talk
      • Watch recording

        KEEPs That We Deserve

        KEEPs that we have been waiting for and have finally got, the ones that raise questions and the ones that raise open doubts.

        • Alexander Nozik

          Scientific Programming Centre

        • Roman Elizarov

          Yandex

        • Alexander Sokolinsky

          Scientific Programming Centre

        Room 3In RussianRUComplexity -For practicing engineers
      • Watch recording

        Kotlin Flow Through the Lens of Real-World Tasks in SberDevices: A Game of Flows

        We'll take a look at how exactly Kotlin Flow handles one of the heaviest services on the web. Only real examples and no tedious retelling of documentation!

        • Ivan Grishov

          SberDevices

        • Nikita Petrenko

          SberDevices

        Room 3In RussianRUComplexity -For practicing engineers
      • Watch recording

        From Postman To Code: Connekt and a New Look at API Testing

        API often has to be checked manually — Postman, curl, Insomnia, HTTP clients in the IDE, each with their own limitations. Connekt combines these scenarios and turns manual checks into live code that is reusable. The talk provides a comparison of approaches and a look "under the hood" of the tool.

        • Aleksander Shustanov

          Haulmont

        Room 3In RussianRUComplexity -Introduction to technology
      • Watch recording

        Kotlin Flow Through the Lens of Real-World Tasks in SberDevices: Solving the Problems of Callback Hell and Backpressure

        I'll tell you and show you with real-world code examples how we use coroutines and flow at SberDevices to solve non-standard tasks. We'll consider the problem of the transition between the world of callbacks and the world of coroutines. I'll show you how we implemented lazy subscriptions to our backend messages and used them to solve the backpressure problem for a shared queue for messaging with the backend.

        • Maksim Sidorov

          SberDevices

        Room 3In RussianRUComplexity -Hardcore. Really hard and demanding talk, you'll understand only if you're an experienced engineer.
    • Tooling

      4
      • Watch recording

        How To Exit Vim and Tame IDEA

        Increasing the efficiency of writing code in IntelliJ IDEA using Vim.

        • Aleksandr Pakhomov

          Unison

        Room 3In RussianRUComplexity -Introduction to technology
      • Watch recording

        Kubernetes Is a Base for a Spring Developer

        A modern senior developer working with Spring is simply obliged to understand Kubernetes. In the talk, you will find out what you need to know, what the pitfalls are, what to look for, and how to use deployment tools in Kubernetes.

        • Ilya Kuchmin

          Amplicode

        Room 1In RussianRUComplexity -Introduction to technology
      • Watch recording

        Java Debugging Ultimate Guide

        I will tell you about the structure and operation of the main debugging tools in JVM. I will give examples of debugging distributed applications, and also tell you about other non-trivial methods of debugging in JVM.

        • Aleksandr Tokarev

          Yandex

        Room 1In RussianRUComplexity -For practicing engineers
      • Watch recording

        How the Compiler Sees the Code. Graph Vulnerability Search

        How does source code turn into graphs, how do compilers work with these structures, and how can developers put them to use? We’ll explore the compiler frontend’s internal representations through a practical example of taint analysis.

        • Konstantin Volokhovskii

          PVS-Studio

        Room 3In RussianRUComplexity -For practicing engineers
    • JDK

      4
      • Watch recording

        Hot JEPs 25: Anniversary

        Java 25 was released on September 16, and according to the tradition of JPoint and Joker, we will analyze all the key changes in detail.

        • Andrey Kuleshov

          Yandex Infrastructure

        • Gregory Koshelev

          Kontur

        • Vadim Tsesko

          01.tech

        Room 1In RussianRU
      • Watch recording

        Is ThreadLocal Outdated? Detailed Comparison With ScopedValue

        With the appearance of virtual threads, ThreadLocal is no longer the only solution for context transfer — Java 21 introduced ScopedValue. But when to use what? Which is faster and uses less memory?

        • Alexander Matorin

          Sber

        Room 1In RussianRUComplexity -Hardcore. Really hard and demanding talk, you'll understand only if you're an experienced engineer.
      • Watch recording

        JDK Flight Recorder in 2025

        JDK Flight Recorder is not a new technology that has undergone several rebirths in its history. The next release of JDK 25 has also not bypassed JDK Flight Recorder and brought with it new features.

        • Alexey Ragozin

        Room 2In RussianRUComplexity -For practicing engineers
      • Watch recording

        Asynchronous Java. Practice Using the Example of Cassandra and Kafka

        I will analyze the pitfalls when interacting with Cassandra and show the implementation of an effective consumer for a variety of Kafka topics in one stream.

        • Sergei Lugovoy

          Koronatech

        Room 2In RussianRUComplexity -For practicing engineers
    • Infrastructure

      4
      • Watch recording

        How to Build Your Own Cloud Using the Components at Hand

        Building your own cloud solution is often considered a rocket science. I'll show you that it's not as scary as it seems.

        • Sergei Samoilov

          MWS Cloud Platform

        Room 3In RussianRUComplexity -Introduction to technology
      • Watch recording

        Java Application Monitoring

        Using examples, I'll show you which metrics I recommend collecting for an abstract web application (for each component, including APIs, databases, and queues) to make it easier and faster to investigate incidents and various performance issues.

        • Anastasiia Tushkanova

          Yandex

        Room 2In RussianRUComplexity -Introduction to technology
      • Watch recording

        Managing the Cloud Without Attracting the Users' Attention

        Let's talk about the history of degradations, how they were found and how they were fixed, and what accidents happened.

        • Aleksei Volkov

          VK

        Room 2In RussianRUComplexity -For practicing engineers
      • Watch recording

        From Postman To Code: Connekt and a New Look at API Testing

        API often has to be checked manually — Postman, curl, Insomnia, HTTP clients in the IDE, each with their own limitations. Connekt combines these scenarios and turns manual checks into live code that is reusable. The talk provides a comparison of approaches and a look "under the hood" of the tool.

        • Aleksander Shustanov

          Haulmont

        Room 3In RussianRUComplexity -Introduction to technology
    • Spring

      3
      • Watch recording

        From Antipattern to a Tool: The Hidden Benefits of an Open Session

        We will discuss the issue of the development with Spring in conjunction with JPA, the related performance problem, and also suggest a solution.

        • Ilya Sazonov

          Axiom JDK

        • Fedor Sazonov

          OpenIDE

        Room 1In RussianRUComplexity -For practicing engineers
      • Watch recording

        Spring Data JPA: Non-Obvious Performance Issues

        Why the service layer should return an Entity, not a DTO. Why fetching small collections can lead to million-dollar datasets. Is it worth fetching deep-nested entities. How turning off autocommit can dramatically increase application throughput.

        • Semyon Kirekov

          Avito

        Room 1In RussianRUComplexity -For practicing engineers
      • Watch recording

        OAuth 2, JWT, OIDC. Everything That Was Not Told to Us in Spring

        When it comes to OAuth 2 and working with JWT, a lot of questions arise while writing code and you have to remember a lot of nuances. The talk contains everything that Google is most often asked about. For security lovers and understanders, in one narrative using the example of Spring.

        • Pavel Kislov

          Amplicode

        Room 2In RussianRUComplexity -For practicing engineers
    • DevEx

      3
      • Watch recording

        From Programming Languages to Developer Experience

        What a programmer's job consists of, where the inefficiencies and optimization possibilities are in it, what cognitive load is and how we deal with it.

        • Roman Elizarov

          Yandex

        Room 1In RussianRUComplexity -Academic talk
      • Watch recording

        How To Exit Vim and Tame IDEA

        Increasing the efficiency of writing code in IntelliJ IDEA using Vim.

        • Aleksandr Pakhomov

          Unison

        Room 3In RussianRUComplexity -Introduction to technology
      • Watch recording

        Kubernetes Is a Base for a Spring Developer

        A modern senior developer working with Spring is simply obliged to understand Kubernetes. In the talk, you will find out what you need to know, what the pitfalls are, what to look for, and how to use deployment tools in Kubernetes.

        • Ilya Kuchmin

          Amplicode

        Room 1In RussianRUComplexity -Introduction to technology
    • Design and Architecture

      2
      • Watch recording

        Retries: Love on the Third Try

        I will trace the path of retries from repeated attempts in real life to their implementation in microservice architectures. I'll tell you how retries have evolved in life, programming, and the Java ecosystem. Which strategies and tools help to achieve reliability, and which ones break everything.

        • Dmitrii Frolov

          T-Bank

        Room 1In RussianRUComplexity -For practicing engineers
      • Watch recording

        OAuth 2, JWT, OIDC. Everything That Was Not Told to Us in Spring

        When it comes to OAuth 2 and working with JWT, a lot of questions arise while writing code and you have to remember a lot of nuances. The talk contains everything that Google is most often asked about. For security lovers and understanders, in one narrative using the example of Spring.

        • Pavel Kislov

          Amplicode

        Room 2In RussianRUComplexity -For practicing engineers
    • Databases

      2
      • Watch recording

        From Antipattern to a Tool: The Hidden Benefits of an Open Session

        We will discuss the issue of the development with Spring in conjunction with JPA, the related performance problem, and also suggest a solution.

        • Ilya Sazonov

          Axiom JDK

        • Fedor Sazonov

          OpenIDE

        Room 1In RussianRUComplexity -For practicing engineers
      • Watch recording

        Spring Data JPA: Non-Obvious Performance Issues

        Why the service layer should return an Entity, not a DTO. Why fetching small collections can lead to million-dollar datasets. Is it worth fetching deep-nested entities. How turning off autocommit can dramatically increase application throughput.

        • Semyon Kirekov

          Avito

        Room 1In RussianRUComplexity -For practicing engineers
    • Languages

      2
      • Watch recording

        From Programming Languages to Developer Experience

        What a programmer's job consists of, where the inefficiencies and optimization possibilities are in it, what cognitive load is and how we deal with it.

        • Roman Elizarov

          Yandex

        Room 1In RussianRUComplexity -Academic talk
      • Watch recording

        Is ThreadLocal Outdated? Detailed Comparison With ScopedValue

        With the appearance of virtual threads, ThreadLocal is no longer the only solution for context transfer — Java 21 introduced ScopedValue. But when to use what? Which is faster and uses less memory?

        • Alexander Matorin

          Sber

        Room 1In RussianRUComplexity -Hardcore. Really hard and demanding talk, you'll understand only if you're an experienced engineer.
    • Data Processing

      2
      • Watch recording

        Asynchronous Java. Practice Using the Example of Cassandra and Kafka

        I will analyze the pitfalls when interacting with Cassandra and show the implementation of an effective consumer for a variety of Kafka topics in one stream.

        • Sergei Lugovoy

          Koronatech

        Room 2In RussianRUComplexity -For practicing engineers
      • Watch recording

        Kotlin Flow Through the Lens of Real-World Tasks in SberDevices: A Game of Flows

        We'll take a look at how exactly Kotlin Flow handles one of the heaviest services on the web. Only real examples and no tedious retelling of documentation!

        • Ivan Grishov

          SberDevices

        • Nikita Petrenko

          SberDevices

        Room 3In RussianRUComplexity -For practicing engineers
    • PostgreSQL

      1
      • Watch recording

        Loading a Hierarchy of Objects from PostgreSQL in a Single Query

        Let's look at different approaches to loading objects from PostgreSQL.

        • Konstantin Plotnikov

          WorkMe.io

        Room 2In RussianRUComplexity -For practicing engineers
    • Off Topic

      6
      • Watch recording

        Joker 2025 Opening Session

        We're talking about schedules, sessions, and activities. Join us in the hall or online to find out what will be waiting for you in the near future!

        • Vladimir Krasilshchik

          01.tech

        • Alexey Fyodorov

          JUG Ru Group

        Room 1In RussianRU
      • Watch recording

        Artificial or Human Intelligence: Choose Your Fighter

        Let's talk about artificial and natural intelligence, wonder whether artificial intelligence will replace developers and what they should prepare for, as well as philosophize about what awaits developers (and everyone else) in the brave new world and how the development process will change.

        • Alexander Popov

          MIPT

        Room 1In RussianRUComplexity -Academic talk
      • No record

        Nexign Rollback Party: Recall Everything

        An emergency has occurred. Nexign’s lead engineer, Java code genius Alexey, has been attacked by cyber saboteurs from a rival organisation and has lost his working memory. We invite party guests to help restore all knowledge about projects, technologies and even the Nexign company.

        Room 2In RussianRUOffline activity, not broadcast or recordedOffline onlyActivity is not recordedREC
      • No record

        Lighting Talks

        Lightning talks are a great format to quickly discuss a topic and find like-minded people. You will enjoy 10-minute talks on professional or near-professional topics and lively discussions.

        • Andrey Kuleshov

          Yandex Infrastructure

        • Petr Portnov

          Ozon

        Room 3In RussianRUOffline activity, not broadcast or recordedOffline onlyActivity is not recordedREC
      • Watch recording

        Quantum Technologies: Towards Practical Challenges

        Today, quantum technologies are one of their most rapidly developing areas. Already today, quantum computers are beginning to solve practical problems in the field of optimization and machine learning, quantum communications are being implemented in telecommunication systems, and quantum sensors are being used for tasks, for example, in the field of biomedicine. Understanding the possibilities of quantum technologies is a step towards understanding the future of the world.

        • Aleksei Fedorov

          Russian Quantum Center / MISIS

        Room 1In RussianRUComplexity -Academic talk
      • Watch recording

        Joker 2025 Closing Session

        We'll be summarize the results of the conference, recall the highlights and tell you about our future plans. Join us in the hall or online so you don't miss anything!

        • Gregory Koshelev

          Kontur

        • Alexey Fyodorov

          JUG Ru Group

        Room 1In RussianRU
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