launcher.md

This is the specification for the launcher.ini file, which controls how Why behaves.

Requirements

• Must be named launcher.ini
• Must exist in the same directory as Why
• Must have classpath specified
• Must have mainclass specified

Options

Key	Type	Default Value	Required	Description
jvm_install	String (path), can be relative by preceding with './'	None	false, unless either allows_system_java and allows_java_lookup is enabled	The path to the location of the jvm.dll - it will recursively search into this path up to a depth of 5 for the jvm.dll
allow_system_java	bool	true	false	Whether the launcher should use the Java listed in the Path
allow_java_location_lookup	bool	true	false	Whether the launcher should check common Java installation directories for a Java install
mainclass	String (as it would appear in a jar manifest)	None	true	The main class, as it would appear in a jar manifest
launch_options	String (path), can be relative by preceding with './`	None	false	The Launch4J-style config to read JVM options from
maximum_heap_percentage	integer	None	false	Sets the -Xmx to this value if missing from the user launch args
classpath	String, same as the launch argument - ';' separated paths	None	true	Sets the classpath; If given a jar, it will respect the jar manifest's classpath entry
min_java	integer	None (0)	false	Only tries to run Java that is equal to or greater than this Java version
check_main_class	bool	true	false	whether the launcher should check check the main class' Java version requirement and use that as the min_java if the current min_java is not specified or less than the found main class requirement. Otherwise, use the specified min_java
use_previous_jvm	bool	false	false	Whether the launcher should check if the selected JVM has a previous instance opened, and if so, use that instance instead of making a new one. On Linux and Windows, it is typical to open a new instance of the application for file associations, this allows that behavior to be overruled