VSCode Java doesn't handle .classpath files properly

Environment

• Operating System: Windows
• JDK version: 1.8.0_171
• Visual Studio Code version: 1.25.1
• Java extension version: 0.29.0

Steps To Reproduce

1. Copy, write, or otherwise create an Eclipse-style .classpath file, specifying a src directory.
2. Create an empty foo.java file in that directory

Current Result

Popup: foo.java isn't on the classpath.

Expected Result

No popup, working go-to-definition and similar project handling.

Additional Information

It is not entirely clear from the website that 'More information' leads to what precisely needs to be copied for the vscode-java to properly build the classpath, so if the answer turns out to be "you need more than just the .classpath", the issue just changes to "the documentation on 'Classpath is incomplete' does not provide sufficient information to actually resolve the issue."

(Also, note that the error is different from that one given when there is no classpath present. vscode-java clearly sees that there's a file there, but isn't reading it correctly.)

bugrepro.zip

从附加的 bugrepro.zip 开始，使用 Eclipse-style .classpath 文件、一个 src 目录和空的 foo.java 重现该行为。检查 VSCode Java extension 如何处理 .classpath 和“Classpath is incomplete”信息；完成的标准是弹窗不再出现，并且 go-to-definition 对该项目有效。