Examples

Input (config.properties)

# Application
app.name=MyApp
app.version=1.0.0
app.debug=true

# Database
database.host=localhost
database.port=5432
database.name=mydb

Default (nested)

flatted: false — dotted keys become nested objects:

{
  "app": {
    "name": "MyApp",
    "version": "1.0.0",
    "debug": "true"
  },
  "database": {
    "host": "localhost",
    "port": "5432",
    "name": "mydb"
  }
}

Values stay strings (for example the literal "true").

Flattened (flatted, delimiter: "_")

{
  "app_name": "MyApp",
  "app_version": "1.0.0",
  "app_debug": "true",
  "database_host": "localhost",
  "database_port": "5432",
  "database_name": "mydb"
}

Uppercase (uppercase: true)

Keys are transformed; shape stays nested or flat depending on options:

{
  "APP": {
    "NAME": "MyApp",
    "VERSION": "1.0.0",
    "DEBUG": "true"
  },
  "DATABASE": {
    "HOST": "localhost",
    "PORT": "5432",
    "NAME": "mydb"
  }
}