question: private static float systemPropertyValue ( String name ) { String floatString = System . getProperty ( name ) ; if ( floatString == null ) return Float . NaN ; try { return Float . parseFloat ( floatString ) ; } catch ( NumberFormatException ex ) { throw new IllegalArgumentException ( String . format ( "Bad float value in system property %s=%s" , name , floatString ) ) ; } }
target:  Returns the value of the system property, or NaN if not defined.