Noclassdeffounderror: org. Eclipse. Core. runtime. iprogressmonitor package

Add jar package: org. Eclipse. Equinox. common_3.4.0.v20080421-2006.jar (my eclipse is 3.4)

Cause:

 

If you see this Article It is estimated that you have encountered such a problem. When you seem right Code (It should be the first time I met similar code, most of these rapeseed teaching materials or the internet.) After a burst of mouse clicks on the keyboard, I ran it with excitement, A dialog box like can't find the main class is displayed. One or two lines of Red Java are displayed on the output information of the eclipse console. lang. noclassdeffounderror: ORG/Eclipse/CORE/runtime/iprogressmonitor
Exception in thread "Main" (or similar ). So let me start by saying, continue reading, and you can basically solve your problem here.

You may wonder why you have added the org/Eclipse/CORE/runtime package to the library, careful notification may find that the class that pops up in the console does not exist in the package you add. It's strange that eclispe is doing something?

In fact, it is very simple. The org/Eclipse/CORE/runtime package is not encapsulated under a jar package. They belong to two projects (I think so ). Just as you can see two projects A1 and A2, whose package paths are the same, for example, Com. Binary .*;. At this time, when someone calls you some code, they only tell you how to import the A1 project, which is not mentioned at all. The fact is that you not only need the A1 project, in addition, the A2 Project is required. I want everyone to understand it. Why does eclipse have such a point? I don't have this similar explanation on the Internet, so I hope eclipse can provide a description.

Haha, well, I think everyone's level. In fact, these missing classes are in org. Eclipse. Equinox. Common. Well, let's try it and hurry up.