这里面包含了一百多个JAVA源文件

				This example demonstrates how to protect access to an object using a permission. Only threads with the required permission can access the object. 
				    // Create the object that requires protection
				    String secretObj = "my secret";
				    
				    // Create the required permission that will protect the object
				    Guard guard = new PropertyPermission("java.home", "read");
				    
				    // Create the guard
				    GuardedObject gobj = new GuardedObject(secretObj, guard);
				    
				    // Get the guarded object
				    try {
				        Object o = gobj.getObject();
				    } catch (AccessControlException e) {
				        // Cannot access the object
				    }
				
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