java.lang.NoClassDefFoundError：javax / mail / MessagingException

Question

I've been working on a program that uses the Javamail API to send emails based on time events and certain conditions. The program runs perfectly in Eclipse (newest version) and the javamail and activator jars are in the build path, as are javamail's dependencies. The problem occurs when I export the project as a jar and try to run it. (The stack trace generated is the same that would be if the javamail jar was missing from the Eclipse build path).

The stack trace is as follows:

`Exception in thread "Timer-1" java.lang.NoClassDefFoundError: javax/mail/MessagingException
at SpaceCheck.HourlySpaceAlerts(SpaceCheck.java:212)
at WarningReports.run(WarningReports.java:21)
at java.util.TimerThread.mainLoop(Unknown Source)
at java.util.TimerThread.run(Unknown Source)
Caused by: java.lang.ClassNotFoundException: javax.mail.MessagingException
at java.net.URLClassLoader$1.run(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 4 more`

Thank you for your help.

Answer 1

假设您将javamail和其他依赖项放在相对于导出的jar的lib/文件夹中，则必须在清单文件中声明这些jar：

Class-Path: lib/javamail.jar

Answer 2

You can also get Java EE libs by adding one of the software REPOs at this url.

http://download.eclipse.org/tools/orbit/downloads/