Java Security

To run these applets with Java VM 1.1 build in MSIE4 and Navigator 4.5 and better browsers follow this link. To run the applets here and read the instructions scroll to the bottom of the page.




There are three applets on this page. First applet during its start determins if the Java security manager is loaded and inquires if the terminating of Java VM (VM exit), reading and writing files, execution of programs and printing are allowed and displays the answers. If you did not give your browser special permissions all answers should be negative. Further you can type path/filename of any file into narrow text field above the submit button and press enter or click submit. Some of the browsers allow to give permission for reading, writing and deleting of certain file even if general permission of operations on files was not given. Answer will show if these operations may be carried out on the named file. When you click the submit button and the field for file name is empty, the applet will display again, if printing is allowed and if java VM is allowed to exit.
The second applet checks if it can read or write a file on a different way. Type the path/filename of a short text file in the narrow input field above the buttons and click open. If the reading of the file is not allowed its name will be replaced with a message saying that reading is not permitted. In oposite case the contents of the file appear in the large text area above. You can also type few words in the large text area and type path/filename of a nonexistent file in the narrow input field. If you click save and writing of the named file is permitted a file will be created and the words written to it. If the named file exists, it will be overwritten. If writing of the file is not allowed its name in the imput field will be replaced by the message "Writing of the submitted file not allowed." All entered pathnames in both applets must not contain spaces. If you are using Windows and they do use MS-DOS names instead.
Last applet examins the possibility to start an application from an applet. Applets parameters determin the class name of the aplication and parameters passed to its main function. Click on the button will start a miniature application that does nothing but its window has all usual system functions. When you try to close the window a dialog appears inquiring if you want to terminate java VM. Choose no unless you are sure that the exit is not allowed and VM cannot terminate. You should be able to give file reading and writing permission without giving the permission for the virtual machine to terminate. Check with the first applet if it can be successfully done.