E.4 PropertiesLauncher Features
PropertiesLauncher has a few special features that can be enabled with external properties (System properties, environment variables, manifest entries or application.properties).
| Key | Purpose |
|---|---|
loader.path |
Comma-separated Classpath, e.g. lib,${HOME}/app/lib. Earlier entries take precedence, just like a regular -classpath on the javac command line. |
loader.home |
Location of additional properties file, e.g. /opt/app (defaults to ${user.dir}) |
loader.args |
Default arguments for the main method (space separated) |
loader.main |
Name of main class to launch, e.g. com.app.Application. |
loader.config.name |
Name of properties file, e.g. loader (defaults to application). |
loader.config.location |
Path to properties file, e.g. classpath:loader.properties (defaults to application.properties). |
loader.system |
Boolean flag to indicate that all properties should be added to System properties (defaults to false) |
Manifest entry keys are formed by capitalizing initial letters of words and changing the separator to “-” from “.” (e.g. Loader-Path). The exception is loader.main which is looked up as Start-Class in the manifest for compatibility with JarLauncher).
![[Tip]](Spring Boot Reference Guide_files/tip.png) |
Tip |
|---|---|
Build plugins automatically move the Main-Class attribute to Start-Class when the fat jar is built. If you are using that, specify the name of the class to launch using the Main-Class attribute and leave out Start-Class. |
Environment variables can be capitalized with underscore separators instead of periods.
loader.homeis the directory location of an additional properties file (overriding the default) as long asloader.config.locationis not specified.loader.pathcan contain directories (scanned recursively for jar and zip files), archive paths, or wildcard patterns (for the default JVM behavior).loader.path(if empty) defaults tolib(meaning a local directory or a nested one if running from an archive). Because of thisPropertiesLauncherbehaves the same asJarLauncherwhen no additional configuration is provided.- Placeholder replacement is done from System and environment variables plus the properties file itself on all values before use.