The last part of the Quick Tour of Controlling Applications lesson shows how an application can be run under a security manager by invoking the interpreter with the new -Djava.security.manager command-line argument. But what if the application to be invoked resides inside a JAR file?

One of the interpreter options is the -cp (for class path) option, that lets you specify a search path for application classes and resources. Therefore, to execute the Count application inside the sCount.jar JAR file, specifying the file C:\TestData\data as its argument, you can type the following command while in the directory containing sCount.jar:

java -cp sCount.jar Count C:\TestData\data

To execute the application with a security manager, add -Djava.security.manager, as shown below:

java -Djava.security.manager -cp sCount.jar Count C:\TestData\data

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Important:  When you run this command, your Java interpreter will throw an exception shown below:

Exception in thread "main" java.security.AccessControlException:
access denied (java.io.FilePermission C:\TestData\data read)
    at java.security.AccessControlContext.checkPermission(Compiled Code)
    at java.security.AccessController.checkPermission(Compiled Code)
    at java.lang.SecurityManager.checkPermission(Compiled Code)
    at java.lang.SecurityManager.checkRead(Compiled Code)
    at java.io.FileInputStream.(Compiled Code)
    at Count.main(Compiled Code)

In this example, AccessControlException reported that the count application does not have permission to read the file C:\TestData\data. Your interpreter raised this exception because it will not allow any application running under a security manager to read a file or to access other resources unless it has explicit permission to do so -- usually specified in a grant statement contained in a policy file.

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