Discover IntelliJ IDEA
IntelliJ IDEA helps you stay productive with an array of features for efficient development. This topic provides an overview of common and useful tips to get started.
You can invoke almost any action without leaving the IntelliJ IDEA Editor, which means you can have more screen space because auxiliary controls like toolbars and windows are hidden.
When you use a shortcut to access any tool window, the input focus and context moves to this window. To move the focus back to the editor, press Escape. The following table lists default tool windows and their corresponding shortcuts:
To focus on your code, try Distraction Free Mode, which removes all toolbars, tool windows, and editor tabs. To switch to this mode, on the main menu select View | Enter Distraction Free Mode.
You can also hide all tool windows by pressing Ctrl+Shift+F12 and then restore the layout by pressing this shortcut again.
Most components in IntelliJ IDEA, including tool windows and pop-ups, provide speed search: start typing anything to filter the list or navigate to a particular item by the typed search query.
The following table lists some useful shortcuts related to editing your code:
Move the current line of code
Duplicate a line of code
Remove a line of code
Comment or uncomment a line of code
Comment a block of code
Find in the currently opened file
Find and replace in the current file
Navigate between opened tabs
Expand or collapse a code block in the editor
|Ctrl+NumPad Plus Ctrl+NumPad -|
Highlight usages of a symbol
To expand or shrink the selection based on language constructs, press Ctrl+W and Ctrl+Shift+W.
You can select more than one piece of code at a time. To add the next occurrence of your current selection, press Alt+J. To remove an occurrence, press Shift+Alt+J.
For more information, see Editor basics.
Press Ctrl+Space to invoke Basic Completion for variables, types, methods, expressions, and so on. Press Ctrl+Space twice to show more suggestions, including private members and non-imported static members.
Press Ctrl+Shift+Space to invoke Smart Completion, which is aware of the expected type and data flow, and shows suggestions relevant to the context. Press Ctrl+Shift+Space twice to show more suggestions, including chains.
Press Ctrl+Shift+Enter to invoke Statement Completion, which adds the missing parentheses, brackets, braces, and other necessary formatting.
Press Ctrl+P to see the suggested parameters for a method or constructor. IntelliJ IDEA shows the parameter info for each overloaded method or constructor, and highlights the best match for the parameters already typed.
Use Postfix Completion to transform an existing expression with a postfix that you type after a dot.
For more information, see Code completion.
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.
Navigate to File works similarly by pressing Ctrl+Shift+N, but is used for files and folders. To navigate to a folder, end your expression with the Slash character.
Navigate to Symbol is available by pressing Ctrl+Shift+Alt+N and allows you to find a method or a field by its name.
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:
If you need to open a file in a particular tool window (or Finder/Explorer), you can do so via the Select In action by pressing Alt+F1:
Navigation shortcuts include:
Navigate to class
Navigate to file
Navigate to symbol
Navigate to declaration
Navigate to type hierarchy
Show UML popup
For more details, refer to Source code navigation.
Quick Popup are helpful for checking additional information related to the symbol at the caret. Below is a list of pop-ups you should know if you want to be more productive:
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 several choices are possible.
Extract a constant
Extract a method
Extract a parameter
For more details, refer to Refactoring code.
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.
If you want to set custom options for the Find Usages algorithm, press Ctrl+Shift+Alt+F7, or click the first button on the right panel with search results.
If what you're looking for is plain text, use Find in Path by pressing Ctrl+Shift+F.
For more details, refer to Search for usages in a project.
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 selectingfrom the main menu, or by selecting 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.
For more details, refer to Code inspections.
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.
For more details, refer to Reformatting Source Code.
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 menu.
To quickly perform a VCS operation on the current file, directory, or an entire project, use the VCS operations popup by pressing Alt+`
Once you've configured the VCS settings, you'll see the Version Control tool window. You can switch to it anytime by pressing Alt+9.
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
VCS operations popup
For more details, refer to Version Control with IntelliJ IDEA.
To perform an operation on a branch, either selectfrom the main or context menu, the , or the widget on the right of the status bar.
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.
For more details, refer to Manage branches.
By default, IntelliJ IDEA doesn't automatically compile projects on saving. To compile a project, selectfrom the main menu, or press Ctrl+F9.
For more details, refer to Compiling Applications.
Running and debugging
Once you've created a Run/Debug configuration by selecting 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.
Sometimes, you may want to step into a particular method, but not the first one which will be invoked. In this case, use Smart step into by pressing Shift+F7 to choose a particular method.
Smart step into
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(done automatically for Maven and Gradle projects).
Configure an application server by clicking thepage of the Settings/Preferences dialog.
Configure a run configuration by selecting, then specify the artifacts to deploy and the server to deploy them to.
You can always tell IntelliJ IDEA to build/rebuild your artifacts (once they have been configured) by selecting.
For more details, refer to Working with Application Servers.
Working with build tools (Maven/Gradle)
Once you've imported/created your Maven/Gradle project, you are free to edit its pom.xml or build.gradle files 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:
For pom.xml enable the Import Maven projects automatically option in (Windows and Linux) or (macOS).
For build.gradle, enable the Use auto-import option in of the Settings/Preferences dialog.
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.
For more details, refer to Gradle.
Migrating from Eclipse or NetBeans
You can watch a quick video of IntelliJ IDEA's overview to see what IntelliJ IDEA offers in code completion, inspections, formatting, and so on.