Quick start with Go

1. A new project has no Go files. To create a Go file, perform one of the following actions:

   • In the Project tool window, right-click the parent folder of a project, and select New | Go File.

   • Click the parent folder of a project, press AltInsert, and select Go File.

   • Click the parent folder of a project, navigate to File | New | Go File.

2. In the New Go File dialog, type a name of the file and select whether you want to create an empty Go file (Empty file) or a Go file with the defined main function (Simple application).

   

Refactoring is a process of improving your source code without creating a new functionality. Refactoring helps you keep your code solid , dry, and easy to maintain.

IntelliJ IDEA suggests you the following refactoring options:

• Change signature changes the method or function name; adds, removes, and reorders parameters; assigns default values to new non-variadic parameters.

• Extract refactorings extracts code fragments that can be grouped. You can extract a constant, a variable, a method, and an interface.

• Inline refactoring moves an extracted code fragment to the calling code. An opposite to the Extract refactoring.

• Copy refactoring copies a file, a directory, or a package to a different directory or a package.

• Move refactoring moves source code sections to another package or a file. For example, you can use the Move refactoring to move methods to another package.

IntelliJ IDEA has two types of code completion:

• Basic code completion CtrlSpace helps you complete names of types, interfaces, methods, and keywords within the visibility scope. When you invoke code completion, IntelliJ IDEA analyzes the context and suggests the choices that are reachable from the current caret position. By default, IntelliJ IDEA displays the code completion popup automatically as you type.

• Smart code completion CtrlShiftSpace filters the suggestion list and shows only the types applicable to the current context.

  The following animation shows the difference between basic and smart type-matching completion. Notice the number of variants that are suggested for different completion types

IntelliJ IDEA provides multiple ways to generate common code constructs and recurring elements, which helps you increase productivity. These can be either file templates used when creating a new file, custom or predefined live templates that are applied differently based on the context, various wrappers, or automatic pairing of characters.

Additionally, IntelliJ IDEA provides code completion and Emmet support.

This topic describes ways to generate standard code constructs specific to Java: constructors, method overrides and implementations, getters and setters, and so on. Go to Code | Generate AltInsert to open the popup menu with available constructs that you can generate.

• You can generate getters, setters, constructors, missing methods, and test files.

Use live templates to insert common constructs into your code, such as loops, conditions, declarations, or print statements.

To expand a code snippet, type the corresponding template abbreviation and press Tab. Keep pressing Tab to jump from one variable in the template to the next one. Press ShiftTab to move to the previous variable.

• To see the list of live templates, open settings CtrlAlt0S and navigate to Editor | Live templates.

  Consider the following example of the Hello World program that is coded with Live Templates.

In IntelliJ IDEA, there is a set of code inspections that detect and correct abnormal code in your project before you compile it. The IDE can find and highlight various problems, locate dead code, find probable bugs, spelling problems, and improve the overall code structure.

Inspections can scan your code in all project files or only in specific scopes (for example, only in production code or in modified files).

Every inspection has a severity level — the extent to which a problem can affect your code. Severities are highlighted differently in the editor so that you can quickly distinguish between critical problems and less important things. IntelliJ IDEA comes with a set of predefined severity levels and enables you to create your own.

• To see the list of inspections, open settings CtrlAlt0S and navigate to Editor | Inspections. Disable some of them, or enable others, plus adjust the severity of each inspection. You decide whether it should be considered an error or just a warning.

  For example, the Unreachable code inspection detects parts of code that cannot be executed.

  

As you work in the editor, IntelliJ IDEA analyzes your code, searches for ways to optimize it, and detects potential and actual problems.

As soon as the IDE finds a way to alter your code, it displays a yellow bulb icon in the editor next to the current line. By clicking this icon, you can view the intention actions available in the current context. Intention actions cover a wide range of situations from warnings to optimization suggestions. You can view the full list of intentions and customize them in the Settings dialog CtrlAlt0S.

To see the list of intention actions, open settings CtrlAlt0S and navigate to Editor | Intentions.

1. To apply an intention action, click the bulb icon (or press AltEnter) to open the list of suggestions.

2. Select an action from the list and press Enter.

   For example, you can use an intention action to inject another language in your code:

   

• To run your application ShiftF10, click the Run Application icon in the gutter and select Run <application_name>.

  

Debugging starts with placing breakpoints at which program execution will be suspended so that you can explore program data. Just click the line in the gutter where you want to place a breakpoint.

• To debug your application ShiftF9, click the Run Application icon in the gutter and select Debug <application_name>. Then go through the program execution step by step (see the available options in the Run menu or the Debug tool window).

  For more information, refer to Debugging.