Full build always performed on startup when using project that imports eclipse files

[rsalvador]

We are importing a big java project in vscode-java using eclipse files (.classpath/.project) and on startup vscode-java always performs a full build which takes several minutes.

The reason for the full build seems to be the CLEAN_BUILD done in JDTLanguageServer.didChangeConfiguration(). VS Code always sends a workspace/didChangeConfiguration on startup and that forces a full build even though
the settings didn't change.

Note: if I remove the CLEAN_BUILD from JDTLanguageServer.didChangeConfiguration() the old markers (i.e. warnings/infos) are not imported. They get imported quickly (a few secs) if I replace the CLEAN_BUILD by an incremental build: JDTLanguageServer.buildWorkspace(false).

Environment

• Operating System: Mac OS 10.13.3
• JDK version: 1.8.0_131
• Visual Studio Code version: 1.20.1
• Java extension version: 0.19.0

Steps To Reproduce

1. import java project using eclipse files
2. stop/start vscode and see that a full build is always performed

jdt.log

Current Result

Full build done on startup

Expected Result

Load old errors and only perform incremental build if files changed since last time vscode was opened. Perform full build only if setting/jvm changed.

Additional Informations

[fbricon]

Fixed with eclipse-jdtls/eclipse.jdt.ls#572