我有相同的平台（netbeans 8.0和JDK 8），在其他项目中搜索（内置netbeans 7.4和JDK 7）我在project.properties文件中发现了一点点差异，在<> / nbproject中搜索它，找到该行：

I have the same platform (netbeans 8.0 and JDK 8), searching in other project (build in netbeans 7.4 and JDK 7) I found a little difference in the project.properties file, search it in <>/nbproject, look for the line:

javac.processorpath=\
    ${javac.classpath}:\
    ${libs.eclipselinkmodelgen.classpath}

并将文本更改为以下内容：

and change the text to finally be the following:

javac.processorpath=\
    ${javac.classpath}

这就是全部，我不知道是不是netbeans 8中的错误或者它可能是某些东西g在制作项目的方式上是错误的，但这个修复工作对我来说，更多细节在这个博客条目（西班牙文版）

thats all, I don't know if it's a bug in netbeans 8 or maybe it's something wrong in the way to make the project, but this fix work for me, more details in this blog entry (spanish version)