Errors occurred during the build.

编译时经常出现：

Errors occurred during the build.
Errors running builder 'JavaScript Validator' on project "Demo".
java.lang.NullPointerException

这个主要是JS的校验比较纠结，经常导致编译出错，这时把JavaScript Validator去掉即可。

选择项目--右键Properties--Builders--如果有则取消第一项“JavaScript Validator”的勾。