Ontime/JDK_REQUIREMENTS.md

JDK version for OnTime (User, Driver, Merchant)

Required: JDK 17 or JDK 21

The project uses:

• Gradle 8.9 (gradle-wrapper)
• Android Gradle Plugin 8.5.0 (User app; Driver/Merchant use similar)
• App source/target: Java 11 (Driver, Merchant); User follows Gradle default

Android Gradle Plugin 8.x needs JDK 17 or newer. Use JDK 17 or JDK 21.

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Install JDK

macOS (Homebrew)

# JDK 17 (LTS)
brew install openjdk@17

# Or JDK 21
brew install openjdk@21

Then link and set JAVA_HOME (add to ~/.zshrc or ~/.bash_profile):

# For JDK 17
export JAVA_HOME="$(/usr/libexec/java_home -v 17 2>/dev/null || echo /opt/homebrew/opt/openjdk@17)"
export PATH="$JAVA_HOME/bin:$PATH"

macOS (manual)

1. Download JDK 17 or 21 from Adoptium or Oracle.
2. Install the .pkg.
3. Set JAVA_HOME, e.g. for Adoptium 17 on Apple Silicon:

   export JAVA_HOME=/Library/Java/JavaVirtualMachines/temurin-17.jdk/Contents/Home
   

Windows

1. Download JDK 17 or 21 from Adoptium.
2. Run the installer and note the install path (e.g. C:\Program Files\Eclipse Adoptium\jdk-17).
3. Set environment variables:
   • JAVA_HOME = that path
   • Add %JAVA_HOME%\bin to Path.

Linux (apt)

# JDK 17
sudo apt update
sudo apt install openjdk-17-jdk

# Or JDK 21
sudo apt install openjdk-21-jdk

Set JAVA_HOME if needed (e.g. in ~/.bashrc):

export JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64
export PATH="$JAVA_HOME/bin:$PATH"

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Check version

java -version
javac -version

You should see version 17 or 21.

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Android SDK (required for building)

Gradle needs the Android SDK path. Either:

1. Set ANDROID_HOME (recommended):

   export ANDROID_HOME=$HOME/Library/Android/sdk   # macOS default
   export PATH=$PATH:$ANDROID_HOME/platform-tools:$ANDROID_HOME/tools
   

2. Or use local.properties in each app folder (already created if you opened the project):

   • OnTime_User_live/local.properties
   • OnTime_Driver_live/local.properties
   • OnTime_Merchant_live/local.properties
     Each should contain:

   sdk.dir=/Users/YOUR_USERNAME/Library/Android/sdk
   

   Replace YOUR_USERNAME with your macOS username, or use the path where Android Studio installed the SDK (e.g. Windows: C:\\Users\\You\\AppData\\Local\\Android\\Sdk).

If the SDK is in a different location, edit sdk.dir in each local.properties or set ANDROID_HOME to that path.

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Then build the apps:

./build-debug-apks.sh

Or open OnTime_User_live, OnTime_Driver_live, or OnTime_Merchant_live in Android Studio (it will use the JDK configured in File → Settings → Build → Build Tools → Gradle).