How to open stdout show log

[Hebe970217]

???

[rgrunber]

A lot of this should be made convenient depending on the client you use. Certain clients may create an option like "Open Java Logs" that open all available logs related to JDT-LS. However, I'm assuming you're working with JDT-LS and want to expose such logs for your own client.

When you start JDT-LS, there is an option passed, -data . You can see this option, in the helper script we ship, at https://github.com/eclipse/eclipse.jdt.ls/blob/26d5d9f3ba2581327f46adfcb6d9a1ee8ace2154/org.eclipse.jdt.ls.product/scripts/jdtls.py#L101 . This represents the location at which JDT-LS will store relevant information related to the project(s) it will handle. The server will log to the file .metadata/.log, relative to the -data location provided.

So if you build the eclipse.jdt.ls repo, and then :

$ ./org.eclipse.jdt.ls.product/target/repository/bin/jdtls -data /tmp/jdtls-workspace

$ cat /tmp/jdtls-workspace/.metadata/.log 
!SESSION 2022-10-26 16:21:22.819 -----------------------------------------------
eclipse.buildId=unknown
java.version=17.0.4.1
java.vendor=Red Hat, Inc.
BootLoader constants: OS=linux, ARCH=x86_64, WS=gtk, NL=en_CA
Command-line arguments:  -data /tmp/jdtls-workspace

!ENTRY org.eclipse.jdt.ls.core 1 0 2022-10-26 16:21:24.104
!MESSAGE class org.eclipse.jdt.ls.core.internal.JavaLanguageServerPlugin is started

!ENTRY org.eclipse.jdt.ls.core 1 0 2022-10-26 16:21:24.232
!MESSAGE Main thread is waiting

You can also log the standard output/error streams of the JDT-LS process since some libraries that comprise the server may log there (as opposed to the server log location mentioned above). To do so, simply add the following system property to the commandline : -Djdt.ls.debug=true. The script above gives you the option to pass such an option using --jvm-arg=... Otherwise, you'll have to do it manually. The result is that there will be log files created of the form : .metadata/.out-jdt.ls-${yyyyMMddHHmmss}.log & .metadata/.error-jdt.ls-${yyyyMMddHHmmss}.log relative to the data location mentioned above. You can see this behaviour at https://github.com/eclipse/eclipse.jdt.ls/blob/26d5d9f3ba2581327f46adfcb6d9a1ee8ace2154/org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/JavaLanguageServerPlugin.java#L167-L169

https://github.com/eclipse/eclipse.jdt.ls/blob/26d5d9f3ba2581327f46adfcb6d9a1ee8ace2154/org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/JavaLanguageServerPlugin.java#L492