IntelliJ IDEA 2016.2 Help

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.

User interface

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.

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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 Escape.

Below is a list of shortcuts that invoke the tool windows you will most often need:

Tool WindowShortcut
ProjectAlt+1
Version ControlAlt+9
RunAlt+4
DebugAlt+5
TerminalAlt+F12
EditorEscape

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.

The Navigation Bar is a compact alternative to the Project tool window. To access the Navigation Bar, press Alt+Home.

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Most components in IntelliJ IDEA (both tool windows and pop-ups) provide speed search. This feature allows you to filter a list, or navigate to a particular item by using a search query.

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Refer to Guided Tour around the User Interface, Editor. and Tool Windows.

Code completion

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 dot.

Editor basics

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:

ActionDescription
Move the current line of codeCtrl+Shift+Up Ctrl+Shift+Down
Duplicate a line of codeCtrl+D
Remove a line of codeCtrl+Y
Comment or uncomment a line of codeCtrl+Slash
Comment a block of codeCtrl+Shift+Slash
Find in the currently opened fileCtrl+F
Find and replace in the current fileCtrl+R
Next occurrenceF3
Previous occurrenceShift+F3
Navigate between opened tabs Alt+Right Alt+Left
Navigate back/forward Ctrl+Alt+Left Ctrl+Alt+Right
Expand or collapse a code block in the editor Ctrl+NumPad Plus Ctrl+NumPad -
Create new...Alt+Insert
Surround withCtrl+Alt+T
Highlight usages of a symbolCtrl+F7

To expand a selection based on grammar, press Ctrl+W. To shrink it, press Ctrl+Shift+W.

IntelliJ IDEA can select more than one piece of code at a time. You can select/deselect any piece of code via Alt+J, or by clicking a code selection and pressing Shift+Alt+J.

Refer to Editor.

Navigation

Recent files

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:

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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.

Structure

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 pop-up shows you the structure of a file, and allows you to quickly navigate to any of them:

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Select in

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:

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Navigation shortcuts include:

ActionShortcut
Search everywhereDouble Shift
Navigate to classCtrl+N
Navigate to fileCtrl+Shift+N
Navigate to symbolCtrl+Shift+Alt+N
Recent filesCtrl+E
File structureCtrl+F12
Select inAlt+F1
Navigate to declarationCtrl+B
Navigate to type hierarchyCtrl+H
Show UML pop-upCtrl+Alt+U

Refer to Navigating Through the Source Code.

Quick pop-ups

Quick Pop-ups 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:

ActionShortcut
DocumentationCtrl+Q
Quick definitionCtrl+Shift+I
Show usagesCtrl+Alt+F7
Show implementationCtrl+Alt+B

Refactoring basics

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.

ActionShortcut
RenameShift+F6
Extract variableCtrl+Alt+V
Extract fieldCtrl+Alt+F
Extract a constantCtrl+Alt+C
Extract a methodCtrl+Alt+M
Extract a parameterCtrl+Alt+P
InlineCtrl+Alt+N
CopyF5
MoveF6
Refactor thisCtrl+Shift+Alt+T

Refer to Refactoring Source Code.

Finding usages

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.

Refer to Finding Usages.

Inspections

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.

Refer to Code Inspection.

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:

ActionShortcut
Reformat codeCtrl+Alt+L
Auto-indent linesCtrl+Alt+I
Optimize importsCtrl+Alt+O

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 pop-up by pressing Alt+Back Quote

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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:

ActionShortcut
Version Control tool windowAlt+9
VCS operations pop-upAlt+Back Quote
Commit changesCtrl+K
Update projectCtrl+T
Push commitsCtrl+Shift+K

Branches

To perform an operation on a branch, either select Branches from the VCS main or context menu, the VCS operations pop-up, 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.

Make

By default, IntelliJ IDEA doesn't automatically compile projects on saving. To compile a project, select Build | Make Project from the main menu, or press Ctrl+F9.

Refer to Compiling Applications.

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.

ActionShortcut
RunShift+F10
DebugShift+F9

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.

ActionShortcut
Toggle breakpointCtrl+F8
Step intoF7
Smart step intoShift+F7
Step overF8
Step outShift+F8
ResumeF9
Evaluate expressionAlt+F8

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.

Application servers

To deploy your application to a server:

  1. Configure your artifacts by selecting File | Project Structure | Artifacts (done automatically for Maven and Gradle projects).
  2. Configure an application server by clicking the Application Servers page of the Settings/Preferences dialog.
  3. Configure a run configuration by selecting Run | Edit Configurations, 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 Build | Build Artifacts.

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 File | Settings | Build, Execution, Deployment | Build Tools | Maven | Importing (Windows and Linux) or IntelliJ IDEA | Preferences | Build, Execution, Deployment | Build Tools | Maven | Importing (OS X).
  • For build.gradle, enable the Use auto-import option in Build, Execution, Deployment | Build Tools | Gradle of the Settings/Preferences dialog.

For manual synchronization, use the corresponding action on the Maven/Gradle tool window toolbar: refresh.

Note that any goal or task can be attached to be run before a run configuration.

Refer to Build Tools.

Migrating from Eclipse or NetBeans

If you are considering the possibility to migrate from Eclipse or NetBeans to IntelliJ IDEA, refer to the corresponding migration guides.

What's next

We strongly advise you to read the documentation. Also you might find it useful to refer to the Java tutorials under Java SE, and also to the tutorial on Java EE.

See Also

Last modified: 13 September 2016