IntelliJ IDEA

IDE for JVM languages including Java, Kotlin, and Scala.

When to Use

• Java/Kotlin development
• Spring Boot applications
• Gradle/Maven projects
• Android development (via Android Studio)

Quick Start

// Create new project: File -> New -> Project
// Select: Kotlin, Gradle (Kotlin DSL)

fun main() {
    println("Hello, World!")
}

Core Concepts

Essential Shortcuts

# Navigation
Cmd/Ctrl + Shift + F    - Find in files
Cmd/Ctrl + E            - Recent files
Cmd/Ctrl + B            - Go to declaration
Cmd/Ctrl + Shift + O    - Go to file

# Refactoring
Shift + F6              - Rename
Cmd/Ctrl + Alt + M      - Extract method
Cmd/Ctrl + Alt + V      - Extract variable
Cmd/Ctrl + Alt + L      - Reformat code

# Running
Shift + F10             - Run
Shift + F9              - Debug
Cmd/Ctrl + Shift + F10  - Run current file

Run Configurations

<!-- .idea/runConfigurations/Main.xml -->
<component name="ProjectRunConfigurationManager">
  <configuration name="Main" type="JetRunConfigurationType">
    <option name="MAIN_CLASS_NAME" value="com.example.MainKt" />
    <option name="VM_PARAMETERS" value="-Xmx512m" />
    <option name="PROGRAM_PARAMETERS" value="--debug" />
    <module name="myproject.main" />
  </configuration>
</component>

Common Patterns

Live Templates

# Create: Settings -> Editor -> Live Templates

# Template: logd
Log.d(TAG, "$END$")

# Template: sout
System.out.println($END$);

# Template: test (for JUnit)
@Test
fun `$NAME$`() {
    $END$
}

Code Inspections

<!-- .idea/inspectionProfiles/Project_Default.xml -->
<component name="InspectionProjectProfileManager">
  <profile version="1.0">
    <inspection_tool class="KotlinDeprecation" enabled="true" level="WARNING" />
    <inspection_tool class="UnusedSymbol" enabled="true" level="WARNING" />
  </profile>
</component>

Best Practices

Do:

• Use intention actions (Alt+Enter)
• Configure code style per project
• Use structural search & replace
• Learn keyboard shortcuts

Don't:

• Commit .idea files blindly
• Ignore code inspections
• Skip indexing process
• Disable type hints

Troubleshooting

Issue	Cause	Solution
Slow IDE	Low heap	Increase in Help > Edit Custom VM Options
Red symbols	Indexing incomplete	Wait or invalidate caches
Gradle sync failed	JDK mismatch	Check Project Structure > SDKs

References

• IntelliJ Documentation
• IntelliJ Tips