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See the Policy File Effects

In the previous steps, you created an entry in the raypolicy policy file granting code signed by "susan" permission to read files from the C:\TestData\ directory (or the testdata directory in your home directory if you're working on Solaris). Now you should be able to successfully execute the Count program to read and count the characters in a file from the specified directory, even when you run the application with a security manager.

As described at the end of the Quick Tour of Controlling Applets(in the Java Security 1.2 trail) lesson, there are two possible ways you can have the raypolicy file be considered as part of the overall policy, in addition to the policy files specified in the security properties file:

  1. Approach 1: Specify the additional policy file in a property passed to the runtime system, or
  2. Approach 2: Add a line in the security properties file specifying the additional policy file

Approach 1: Indicating a policy file in the interpreter call

You can use a "-Djava.security.policy" command-line argument to specify a policy file that should be used in addition to or instead of the ones specified in the security properties file.

To run the Count application and have the raypolicy policy file included, type the following (while in the directory containing the sCount.jar and raypolicy files): 

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

The program should report the number of characters in the specified file.

If it still reports an error, there must be something wrong in the policy file. Use the Policy Tool to check the permission you just created in the previous step and change any typos or other errors.

Approach 2: Modifying the security properties file

You can specify a number of URLs (including ones of the form "http://") in policy.url.n properties in the security properties file, and all the designated policy files will get loaded.

So one way to have your raypolicy file's policy entries considered by the interpreter is to add an entry indicating that file in the security properties file.

Important: If you are running your own copy of the JDK, you can easily edit your security properties file, as described below. If you are running a version shared with others, you may only be able to modify the system-wide security properties file if you have write access to it or if you ask your system administrator to modify the file when appropriate. However, it's probably not appropriate for you to make modifications to a system-wide policy file for this tutorial test; we suggest that you just read the following to see how it's done, or that you install your own private version of the JDK to use for the tutorial lessons.
The security properties file is located at 
java.home\lib/security\java.security
Note: java.home indicates the directory into which the JDK was installed.

To modify the security properties file, open it in an editor suitable for editing an ASCII text file. Then add the following line after the line starting with "policy.url.2": 

policy.url.3=file:/C:/Test/raypolicy
Next, in your command window:
  1. Go to the directory containing the sCount.jar file, that is, the C:\Test directory.

  2. Type the following: 
    java -Djava.security.manager -cp sCount.jar Count C:\TestData\data

As with Approach 1, if the program still reports an error, there must be something wrong with the policy file. Use the Policy Tool to check the permission you just created in the previous step and change any typos or other errors.

Important: Before continuing, you may want to delete the line you just added in the security properties file (or comment it out), since you probably do not want the raypolicy file included when you are not running the tutorial lessons.

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