VSCode shows errors in Java source: unresolved imports

[hmf]

I recently started experimenting with VSCode + Metals. I am using VSCode with Mill. I successfully imported the build file and bloop seems to be working correctly save for one issue - I get the message Skipped configuration of SemanticDB in unsupported 3.0.0-M3 projects (see full log below).

I also get the following message (see full log below): WARN Could not find java sources in None. Java symbols will not be available.. However, I do have Java source code. What is more, VSCode's Java extension launches a task - Java build. The result is that I now have many import cannot be resolved errors.

So my question is, how should I set-up Metals so that it finds the Java sources and the Java extensions not interfere with Mill's bloop?

TIA

Starting the bsp launcher for bloop...
Opening a bsp server connection with 'bsp --protocol local --socket /tmp/bsp-launcher10465251025967889908/bsp.socket'...
Waiting for the bsp connection to come up...
Waiting for the bsp connection to come up...
No server running at 127.0.0.1:8212, let's fire one...
Resolving ch.epfl.scala:bloop-frontend_2.12:1.4.6-15-209c2a5c...
Starting bloop server at 127.0.0.1:8212...
Attempting a connection to the server...
Attempting a connection to the server...
Attempting a connection to the server...
�[0m�[32m[D]�[0m Loading workspace settings from bloop.settings.json
�[0m�[32m[D]�[0m Loading 2 projects from '/home/hmf/VSCodeProjects/pdm_toyadmos/.bloop'...
�[0m�[32m[D]�[0m Loading project from '/home/hmf/VSCodeProjects/pdm_toyadmos/.bloop/dcase2020.json'
�[0m�[32m[D]�[0m Loading project from '/home/hmf/VSCodeProjects/pdm_toyadmos/.bloop/dcase2020.test.json'
�[0m�[32m[D]�[0m Cache miss for scala instance org.scala-lang:scala-compiler:3.0.0-M3.
�[0m�[32m[D]�[0m   => /home/hmf/.cache/coursier/v1/https/repo1.maven.org/maven2/com/google/protobuf/protobuf-java/3.7.0/protobuf-java-3.7.0.jar
�[0m�[32m[D]�[0m   => /home/hmf/.cache/coursier/v1/https/repo1.maven.org/maven2/net/java/dev/jna/jna/5.3.1/jna-5.3.1.jar
�[0m�[32m[D]�[0m   => /home/hmf/.cache/coursier/v1/https/repo1.maven.org/maven2/org/jline/jline-reader/3.15.0/jline-reader-3.15.0.jar
�[0m�[32m[D]�[0m   => /home/hmf/.cache/coursier/v1/https/repo1.maven.org/maven2/org/jline/jline-terminal-jna/3.15.0/jline-terminal-jna-3.15.0.jar
�[0m�[32m[D]�[0m   => /home/hmf/.cache/coursier/v1/https/repo1.maven.org/maven2/org/jline/jline-terminal/3.15.0/jline-terminal-3.15.0.jar
�[0m�[32m[D]�[0m   => /home/hmf/.cache/coursier/v1/https/repo1.maven.org/maven2/org/scala-lang/modules/scala-asm/7.3.1-scala-1/scala-asm-7.3.1-scala-1.jar
�[0m�[32m[D]�[0m   => /home/hmf/.cache/coursier/v1/https/repo1.maven.org/maven2/org/scala-lang/scala-library/2.13.4/scala-library-2.13.4.jar
�[0m�[32m[D]�[0m   => /home/hmf/.cache/coursier/v1/https/repo1.maven.org/maven2/org/scala-lang/scala3-compiler_3.0.0-M3/3.0.0-M3/scala3-compiler_3.0.0-M3-3.0.0-M3.jar
�[0m�[32m[D]�[0m   => /home/hmf/.cache/coursier/v1/https/repo1.maven.org/maven2/org/scala-lang/scala3-interfaces/3.0.0-M3/scala3-interfaces-3.0.0-M3.jar
�[0m�[32m[D]�[0m   => /home/hmf/.cache/coursier/v1/https/repo1.maven.org/maven2/org/scala-lang/scala3-library_3.0.0-M3/3.0.0-M3/scala3-library_3.0.0-M3-3.0.0-M3.jar
�[0m�[32m[D]�[0m   => /home/hmf/.cache/coursier/v1/https/repo1.maven.org/maven2/org/scala-lang/tasty-core_3.0.0-M3/3.0.0-M3/tasty-core_3.0.0-M3-3.0.0-M3.jar
�[0m�[32m[D]�[0m   => /home/hmf/.cache/coursier/v1/https/repo1.maven.org/maven2/org/scala-sbt/compiler-interface/1.3.5/compiler-interface-1.3.5.jar
�[0m�[32m[D]�[0m   => /home/hmf/.cache/coursier/v1/https/repo1.maven.org/maven2/org/scala-sbt/util-interface/1.3.0/util-interface-1.3.0.jar
�[0m�[32m[D]�[0m Skipped configuration of SemanticDB in unsupported 3.0.0-M3 projects
�[0m�[32m[D]�[0m Loading previous analysis for 'dcase2020.test' from '/home/hmf/VSCodeProjects/pdm_toyadmos/.bloop/out/dcase2020.test/dcase2020.test-analysis.bin'.
�[0m�[32m[D]�[0m Loading previous analysis for 'dcase2020' from '/home/hmf/VSCodeProjects/pdm_toyadmos/.bloop/out/dcase2020/dcase2020-analysis.bin'.
�[0m�[32m[D]�[0m Waiting for a connection at local:///tmp/bsp-launcher10465251025967889908/bsp.socket...
The server is listening for incoming connections at local:///tmp/bsp-launcher10465251025967889908/bsp.socket...
Starting thread that pumps stdin and redirects it to the bsp server...
Starting thread that pumps server stdout and redirects it to the client stdout...
2020.12.31 14:13:53 INFO  tracing is disabled for protocol BSP, to enable tracing of incoming and outgoing JSON messages create an empty file at /home/hmf/.cache/metals/bsp.trace.json
2020.12.31 14:13:53 INFO  time: connected to build server in 2.13s
2020.12.31 14:13:53 INFO  Connected to Build server v1.4.6-15-209c2a5c
2020.12.31 14:13:53 INFO  time: imported build in 0.11s
2020.12.31 14:13:55 WARN  Could not find java sources in None. Java symbols will not be available.
2020.12.31 14:13:55 INFO  time: indexed workspace in 1.28s
dez 31, 2020 2:17:43 DA TARDE org.eclipse.lsp4j.jsonrpc.services.GenericEndpoint notify
INFO: Unsupported notification method: $/setTraceNotification
dez 31, 2020 2:19:17 DA TARDE org.eclipse.lsp4j.jsonrpc.services.GenericEndpoint notify
INFO: Unsupported notification method: $/setTraceNotification

[tgodzik]

Thanks for reporting! The issue here is that Metals does not find JDK sources, which might not be installed by default on your machine. The only problem it will have is not jumping to JDK sources, everything else should work.

There is some info here on how to install them: https://askubuntu.com/questions/755853/how-to-install-jdk-sources

[hmf]

I now have no log error and I can now jump to the source code. However, I still have the errors generated by the Java build. Is there a way for the Java extension to play nicely with Metals? For example automatically deactivate them when Metals is active?

TIA

[tgodzik]

Java extension will not work currently with Metals, because there is no way currently to have multiple LSP server interact unfortunately. Best to disable it in a Scala codebase. There some workarounds where you could get it to work nicer, but of the box it will not work, since the Java extension does not have the same information as Metals do.

[hmf]

Best to disable it in a Scala codebase.

Ok. I assume you mean disable the extension in the workspace. If not please correct me.

If you have any links to these workarounds I would appreciate it.
Thank you.

EDIT: for the record
https://github.com/Microsoft/vscode-extension-samples/tree/master/lsp-multi-server-sample