java.lang.InstantiationException: Either "code" or "object" ...

Note: This Java deployment guide describes features released prior to the Java SE 6 update 10 release. See Java Rich Internet Applications Development and Deployment for the latest information.

`java.lang.InstantiationException: either code or object should be specified, but not both`

Symptoms

When running an applet in a browser using the Sun Java Runtime Environment (JRE) implementation, a java.lang.InstantiationException is thrown. The same applet runs without any errors with the Microsoft Virtual Machine (VM).

Cause

There are two possible causes.

Both code and object attributes are specified in the <APPLET> tag:

<APPLET code=MyApplet object=MyApplet.ser width=100 height=100>
</APPLET>

The Sun JRE can access the code or the object attribute, and not both.
A code attribute is specified in the <APPLET> tag, and an object attribute is specified in a <PARAM> tag as shown in the following code:

<APPLET code=MyApplet width=100 height=100>
<PARAM name="object" value="someValue">
</APPLET>

public class MyApplet extends java.applet.Applet
{
        public void init()
        {
               String value = getParameter("object");
        }
        ....
}

The Sun JRE does not support object as a parameter name.

Resolution

        In the first cause eliminate the code attribute in the <APPLET> tag as shown in the following code:

             <APPLET object=MyApplet.ser width=100 height=100>
             </APPLET>

        In the second cause change the parameter name to a different name as shown in the following code:

             <APPLET code=MyApplet width=100 height=100>
             <PARAM name="property1" value="someValue">
             </APPLET>

             public class MyApplet extends java.applet.Applet
             {
                 public void init()
                 {
                         String value = getParameter("property1");
                 }
                 ....
             }

Related Information

None.