Could not load source '': SourceRequest: property 'sourceReference' is missing, null, or empty.

[cshung]

Cannot load source code during Java debugging in a certain scenario.

Environment

• Operating System: OSX
• JDK version: 1.8.0_201
• Visual Studio Code version: 1.30.2
• Java extension version:0.6.0
• Java Debugger extension version:0.17.0

Steps To Reproduce

1. Clone and build the google closure compiler at https://github.com/google/closure-compiler
2. Set a breakpoint at src/com/google/javascript/jscomp/PeepholeCollectPropertyAssignments.java
3. Build the project using maven (instruction included at the front page of the repo)
4. Debug

Current Result

The breakpoint hits, but then loading sour code fails with this error.
Could not load source '': SourceRequest: property 'sourceReference' is missing, null, or empty.

Expected Result

Loading source code should work.

Additional Informations

[testforstephen]

duplicated with microsoft/java-debug#259