IntelliJ IDEA

IntelliJ IDEA is JetBrains' IDE for Java and Kotlin developers and Spring teams, with a free core and an Ultimate subscription adding Spring and data tools.

IntelliJ IDEA gives Java and Kotlin developers one place to write, navigate, refactor, test and debug code across a whole project. JetBrains makes it, alongside the Kotlin language itself and a line of IDEs for other languages. Once offered as two separate products, IntelliJ IDEA now ships as one distribution for Windows, macOS and Linux. Its completion and inspections work from the project's types and symbols, so a suggestion fits the code at the caret. The editor pairs context-sensitive code completion with dozens of framework-specific inspections, such as checks for Spring bean autowiring errors. Refactorings update every reference when a symbol is renamed, moved or extracted, and Find Usages lists each reference across the codebase. The debugger steps through code with breakpoints, watches and expression evaluation, and the test runner marks failed tests in the gutter. IntelliJ Profiler records CPU, memory allocation and thread data from a running program. Database tools connect to live databases to run queries and export data, and UML class diagrams draw the structure of a package. It suits Java and Kotlin developers, and Spring Boot teams on the JVM get the framework support built in. Front-end work fits in the same window, with JavaScript, TypeScript, React, Vue, Angular and Node.js supported beside SQL. JetBrains AI brings AI Assistant chat and completion, plus the Junie agent, into the editor. Developers who review code that AI agents write can check it with the same inspections, tests and debugger. Building and debugging a JVM project stays inside the IDE. Builds run through Maven, Gradle or sbt, and named run configurations keep the arguments and environment variables for each way an application starts. Git commits, branches, changelists and merge conflicts are handled in the IDE, and pull requests from GitHub and GitLab can be reviewed there too. When code has to run on a server, remote development keeps a lightweight client on the laptop and the backend on a remote machine, a dev container or WSL. A Spring Boot developer can write a service, run it from a saved configuration, debug it and commit the fix in one window. JetBrains Marketplace plugins add the other tools a team uses.