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"Invalid bytecode" or "Applet crashed" Java errors

If you get errors like "Invalid bytecode" or "Applet crashed" when trying to view a Java applet, this means that the Java Runtime Environment is having problems interpreting the compiled Java source code of a Java applet. This is often caused by bad coding, or that the compilation of the Java applet (translating it from source code to Java code) went wrong.

A possible cause for this is that the Java applet is compiled for the wrong Java version or that it isn't written according to the official Java specification by Sun Microsystems.

Microsoft's implementation of Java is known to cause such problems, since it differs from Sun Microsystems' Java specification.

As a user, there is little you can do if the Java applet is compiled for Microsoft's version of Java, apart from contacting the webmaster of the site in question about the problem.

If you discover any bugs in Opera's Java handling, you can report them through our Bug Tracking System.

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