need to use Runtime.exec(String command, String env) in that i want to specify , System.setProperty("user.dir",value)
how can i use this in string array of env ,
That isn't going to work.
'System.setProperty' is Java - it has NO meaning for the OS. And even if you set that 'name=value' pair it will only be set in the environment for the 'command' that you use 'exec' to execute; it will not affect your current Java code.