question: private File sessionStore ( String ctxPath ) { String storeDir = System . getProperty ( "catalina.base" ) ; if ( storeDir == null || storeDir . isEmpty ( ) ) { storeDir = System . getProperty ( "java.io.tmpdir" ) ; } else { storeDir += System . getProperty ( "file.separator" ) + "temp" ; } File file = new File ( storeDir , ctxPath . replaceAll ( "/" , "_" ) + ".sessions.ser" ) ; return ( file ) ; }
target:  Return a File object representing the pathname to our persistence file, if any.