问题
I am using Eclipse Oxygen.2 (4.7.2) and Java 9.0.4. I created a project via right-click > Build Path > Configure Build Path... > Libraries. All buttons are disabled like Add JARs, *Add External JARs..., etc.:
Please help me to solve this issue.
回答1:
You first have to select either Modulepath or Classpath.
The Modulepath is a very new thing for Java 9 (here you can watch a short video how it can be used). It exists since the Eclipse Oxygen.1a (4.7.1a), October 11, 2017. In case of doubt, I recommend selecting Classpath.
来源：https://stackoverflow.com/questions/48491394/eclipse-in-the-libraries-tab-all-buttons-are-disabled