Discover IntelliJ IDEA
This guide is intended to help you become more productive with IntelliJ IDEA, and provides an overview of the most important features, together with tips, tricks, and the hottest shortcuts.
The IntelliJ IDEA Editor is special in a number of ways, most notable being is that you can invoke almost any IDE feature without leaving it, which allows you to organize a layout where you have more screen space because auxiliary controls like toolbars and windows are hidden.
Accessing a tool window via its shortcut moves the input focus to it, so you can use all keyboard commands in its context.
When you need to go back to the editor, press
Below is a list of shortcuts that invoke the tool windows you will most often need:
When you want to focus on the code, try the Distraction Free Mode. It removes all toolbars, tool windows, and editor tabs. To switch to this mode, on the main menu select View | Enter Distraction Free Mode.
An alternative to the Distraction Free Mode may be hiding all tool windows by pressing Ctrl+Shift+F12. You can restore the layout to its default by pressing this shortcut once again.
Most components in IntelliJ IDEA (both tool windows and popups) provide speed search. This feature allows you to filter a list, or navigate to a particular item by using a search query.
When you access Basic Completion by pressing Ctrl+Space, you get basic suggestions for variables, types, methods, expressions, and so on. When you call Basic Completion twice, it shows you more results, including private members and non-imported static members.
The Smart Completion feature is aware of the expected type and data flow, and offers the options relevant to the context. To call Smart Completion, press Ctrl+Shift+Space. When you call Smart Completion twice, it shows you more results, including chains.
To let IntelliJ IDEA complete a statement for you, press Ctrl+Shift+Enter. Statement Completion will automatically add the missing parentheses, brackets, braces and the necessary formatting.
If you want to see the suggested parameters for any method or constructor, press Ctrl+P. IntelliJ IDEA shows the parameter info for each overloaded method or constructor, and highlights the best match for the parameters already typed.
The Postfix Completion feature lets you transform an already typed expression to another one based on the postfix you type after a period, the expression type, and its context.
Since in IntelliJ IDEA you can undo refactorings and revert changes from Local History, it makes no sense to ask you to save your changes every time.
The most useful Editor shortcuts are:
To expand a selection based on grammar, press Ctrl+W. To shrink it, press Ctrl+Shift+W.
Most of the time you work with a finite set of files, and need to switch between them quickly. A real time-saver here is an action called Recent Files invoked by pressing Ctrl+E. By default, the focus is on the last accessed file. Note that you can also open any tool window through this action:
Navigate to Class is available by pressing Ctrl+N and supports sophisticated expressions, including camel humps, paths, line navigate to, middle name matching, and many more. If you call it twice, it shows you the results out of the project classes.
When you are not switching between files, you are most probably navigating within a file. The simplest way to do it is to press Ctrl+F12. The popup shows you the structure of a file, and allows you to quickly navigate to any of them:
Navigation shortcuts include:
IntelliJ IDEA offers a comprehensive set of automated code refactorings that lead to significant productivity gains when used correctly. Firstly, don't bother selecting anything before you apply a refactoring. IntelliJ IDEA is smart enough to figure out what statement you're going to refactor, and only asks for confirmation if there are several possible choices.
Find Usages helps you quickly find all pieces of code referencing the symbol at the caret (cursor), no matter if the symbol is a class, method, field, parameter, or another statement. Just press Alt+F7 and get a list of references grouped by usage type, module, and file.
Inspections are built-in static code analysis tools that help you find probable bugs, locate dead code, detect performance issues, and improve the overall code structure.
Most inspections not only tell you where a problem is, but also provide quick fixes to deal with it right away. Press Alt+Enter to choose a quick fix.
Inspections that are too complex to be run on-the-fly are available when you perform code analysis for the entire project. You can do this in one of the following two ways: by selecting Analyze | Inspect Code from the main menu, or by selecting Analyze | Run Inspection by Name to run an inspection by its name.
Note that while inspections provide quick-fixes for code that has potential problems, intentions help you apply automatic changes to code that is correct. To get a list of intentions applicable to the code at the caret, press Alt+Enter.
Code Style and Formatting
IntelliJ IDEA automatically applies a code style you've configured in the Code Style settings as you edit, and in most cases you don't need to call the Reformat Code action explicitly.
Useful formatting shortcuts:
Note that by default, IntelliJ IDEA uses regular spaces for indents instead of tabs. If you have files with lots of indents, you may want to optimize their size by enabling the Use tab character option in the Java code style settings.
Version Control Basics
To check out a project from a Version Control System (VCS), click Checkout from Version Control on the Welcome Screen, or in the main VCS menu.
To quickly perform a VCS operation on the current file, directory, or an entire project, use the VCS operations popup by pressing Alt+Back Quote
Once you've configured the VCS settings, you'll see the Version Control tool window. You can switch to it anytime by pressing N/A.
The Local Changes tab of the Version Control tool window shows your local changes: both staged and unstaged.
Useful VCS shortcuts:
|Version Control tool window||N/A|
|VCS operations popup||Alt+Back Quote|
Note that for multiple repositories, IntelliJ IDEA performs all VCS operations on all branches simultaneously, so you don't need to switch between them manually.
Shelves, stashes and patches help you when you need to store some of the local changes without committing them to the repository. You can then switch to the repository versions of the files, and then come back to your changes later.
Running and Debugging
Once you've created a Run/Debug configuration by selecting Run | Edit Configurations from the main menu, you are able to run and debug your code.
When in the debug mode, you can evaluate any expression by using the Evaluate expression tool, which is accessed by pressing Alt+F8. This tool provides code completion in the same way as in the editor, so it's easy to enter any expression.
|Smart step into||Shift+F7|
If you want to "rewind" while debugging, you can do it via the Drop Frame action. This is particularly helpful if you mistakenly stepped too far. This will no revert the global state of your application, but will at least let you revert to a previous stack frame.
Reloading changes and hot swapping
Sometimes, you need to insert minor changes into your code without shutting down the process. Since the Java VM has a HotSwap feature, IntelliJ IDEA handles these cases automatically when you call Make.
To deploy your application to a server:
- Configure your artifacts by selecting File | Project Structure | Artifacts (done automatically for Maven and Gradle projects).
- Configure an application server by selecting File | Settings | Application Servers.
- Configure a run configuration by selecting Run | Edit Configurations, then specify the artifacts to deploy and the server to deploy them to.
Working with Build Tools (Maven/Gradle)
Once you've imported/created your Maven/Gradle project, you are free to edit its
directly in the editor. Any changes to the underlying build configuration will eventually need to be synced with the project
model in IntelliJ IDEA.
If you want the IDE to synchronize your changes immediately, do the following:
pom.xmlenable the Import Maven projects automatically option in File | Settings | Build, Execution, Deployment | Build Tools | Maven | Importing.
build.gradle, enable the Use auto-import option in Settings | Build, Execution, Deployment | Build Tools | Gradle.
For manual synchronization, use the corresponding action on the Maven/Gradle tool window toolbar: .
Note that any goal or task can be attached to be run before a run configuration.