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<TITLE>Listing All Permissions Granted to Classes Loaded from a URL or Directory (Java Developers Almanac Example)
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<A HREF="../java.security/pkg.html">java.security</A><font color="#666666" class="xsmall-font">
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<B><A HREF="../java.security/pkg.html#Permissions">Permissions</A></B><font color="#666666" class="xsmall-font">
[7 examples]
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<h3>e218. Listing All Permissions Granted to Classes Loaded from a URL or Directory</h3>
A <font color="#0066ff"><i>code base</i></font> is a location of class or jar files specified using a
URL. The URL may refer to a location on the Internet or a directory
in the local file system. This example retrieves all the permissions
granted to a particular class that's been loaded from a code base.
<P> These permissions are effective only if the security manager is
installed (see <a href="../java.security/CustSecurityMgr.html" class="eglink"><b>e212</b> Enabling the Security Manager</a>). However,
with a security manager installed, a class will require permission to
execute <code>Class.getProtectionDomain()</code> and <code>Policy.getPermissions()</code>.
<pre> URL codebase = null;
try {
// Get permissions for a URL
codebase = new URL("http://java.sun.com/");
// Get permissions for a directory
codebase = new File(<font color="#0066ff"><i>"c:\\users\\almanac\\"</i></font>).toURL();
codebase = new File(<font color="#0066ff"><i>System.getProperty("user.home")</i></font>).toURL();
} catch (MalformedURLException e) {
} catch (IOException e) {
}
// Construct a code source with the code base
CodeSource cs = new CodeSource(codebase, null);
// Get all granted permissions
PermissionCollection pcoll = Policy.getPolicy().getPermissions(cs);
// View each permission in the permission collection
Enumeration enum = pcoll.elements();
for (; enum.hasMoreElements(); ) {
Permission p = (Permission)enum.nextElement();
}
</pre>
When the above example is run with the following policy file:
<pre> grant codeBase "http://java.sun.com/-" {
// Give permission to read all system properties
permission java.util.PropertyPermission "*", "read";
};
grant codeBase "file:${user.home}/*" {
// Give permission to execute all runtime-protected methods
permission java.lang.RuntimePermission "*";
};
</pre>
using the following command:
<pre> java -Djava.security.policy==my.policy <font color="#0066ff"><i>MyApp</i></font>
</pre>
the permissions for the URL <code>http://java.sun.com/</code> are:
<pre> (java.util.PropertyPermission * read)
</pre>
and the permissions for the directory <code>System.getProperty("user.home")</code> are:
<pre> (java.lang.RuntimePermission *)
</pre>
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<b>Related Examples</b></font></td>
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e212. <a class="eglink" href="CustSecurityMgr.html?l=rel">
Enabling the Security Manager
</a>
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e213. <a class="eglink" href="CheckPermission.html?l=rel">
Checking Read/Write Permission for a Directory
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e214. <a class="eglink" href="CheckImplies.html?l=rel">
Determining If One Permission Implies Another
</a>
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e215. <a class="eglink" href="CustPerm.html?l=rel">
Creating a Custom Permission
</a>
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e216. <a class="eglink" href="GuardObj.html?l=rel">
Controlling Access to an Object
</a>
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e217. <a class="eglink" href="ListClassPerm.html?l=rel">
Listing All Permissions Granted to a Loaded Class
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See also:
<a class="eglink" href="/egs/java.security/pkg.html?l=rel#Key%20Store">
Key Store
</a>
<a class="eglink" href="/egs/java.security/pkg.html?l=rel#Message%20Digests">
Message Digests
</a>
<a class="eglink" href="/egs/java.security/pkg.html?l=rel#Policy%20Files">
Policy Files
</a>
<a class="eglink" href="/egs/java.security/pkg.html?l=rel#Public%20and%20Private%20Keys">
Public and Private Keys
</a>
<a class="eglink" href="/egs/java.security/pkg.html?l=rel#Signatures">
Signatures
</a>
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