Normally when I right-click my app engine project and choose "Generate cloud endpoint client library" using the Google plugin for Eclipse, it generates the client libraries and automatically copies them into the Android client project.
However, for no apparent reason, the client library is no longer being copied to the client project. In fact, it has been removed (so now I have a lot of errors in my project because it can't find the libraries).
I've tried re-generating the client library which completes without any errors but the problem persists. Interestingly, it seems to complete the process slightly faster than it used to.
I've tried cleaning all projects.
I've tried manually adding the generated source folders from endpoint-libs, but I can't because the generated folders no longer exist. There is also no longer any reference to them in the Java build path for the client project.
I've tried checking out an older version of the code where I know the plugin worked, and the problem occurred there too which leads me to believe it is not a problem in my code.
I also tried deleting the project in eclipse and re-importing everything.
What happened? I've used the generate function many times before and it worked every time until now. I think it started after doing a project clean.
An Update
I followed the suggestion here and was able to generate the client library for one of my endpoints, but the actual .jar file which is needed was not generated (the generated readme file even specifically states the filename and location of the jar but it does not exist).
The issue tracker shows that this issue was resolved (https://code.google.com/p/googleappengine/issues/detail?id=9746).
Also @howettl posted above in the comments that this issue was fixed.
There were some questions in the issue tracking about remote servers being involved and the fix not requiring an update to the GPE. This appears to be related to the fact that there is a Google web service used by the GPE for generating some of the cloud endpoint code.
If this web service is not working (routing issue, server issue, etc), or you don't have a connection to the internet, you will not be able to generate (or regenerate) cloud endpoints for your project.
Also if your generation is slow, it might be due to your internet connection speed.
来源：https://stackoverflow.com/questions/17874217/generate-cloud-endpoint-client-library-suddenly-stopped-working