VisibleGif and running Java

Most users will run VisibleGif as an executable program. Some developers may want to be build the capabilities of VisibleGif into their own applications. Access to the Java classes is a good way of achieving this.

As an example it might be a requirement to encrypt an image, add a digital verification certificate and an expiry date. This would reduce the chances of a particular image being accessed by unauthorised users or by an authorised user after a particular time period.

WhyWaitForever can provide consultancy on these aspects.

Running the Program

The first step is Java

This product uses programs written in the Java programming language. The execution of Java programs requires a Java virtual machine to be installed on the particular computer prior to execution. The Java virtual machine is available from a number of sources.

It is possible that Java (or JRE the minimal version from Sun) has previously been installed. This can be tested by launching a command window (on a Windows 95/98 machine this is called a MS-DOS prompt window and on a Windows NT machine this is called a Command Prompt).

At the prompt in the command window type java.

If Java is not installed a message will be displayed similar to "Bad command or file name" or "The name specified is not recognised as an internal or external command, operable program or batch file.".
If java is installed a series of java usage messages are displayed.

At the prompt in the command window type jre.

If JRE is not installed a message will be displayed similar to "Bad command or file name" or "The name specified is not recognised as an internal or external command, operable program or batch file.".
If JRE is installed a series of java usage messages are displayed.

Sun Microsystems provide extensive information on Java. The recommended source for the Java virtual machine is the Java Runtime Environment (JRE) from Sun Microsystems. JRE provides a minimum standard Java platform for running applications written in the Java programming language. The latest version of the JRE can be downloaded and installed from the above link.

The Java virtual machine can be obtained from a number of download sources though these are more suitable for experienced Java developers.

The examples assume that the JRE version 1.1.8 has been installed. If the Java Development Kit (JDK) has been installed references to "jre" can be replaced with "java" and references to "rt.jar can be replaced with "classes.zip". Note the directory (folder) paths should be amended accordingly.