java version through shell

metals/src/main/scala/scala/meta/internal/builds/ShellRunner.scala

@@ -1,7 +1,10 @@
 package scala.meta.internal.builds
 
+import scala.concurrent.Await
 import scala.concurrent.Future
 import scala.concurrent.Promise
+import scala.concurrent.duration.DurationInt
+import scala.language.postfixOps
 import scala.util.Properties
 
 import scala.meta.internal.metals.Cancelable
@@ -30,6 +33,7 @@ class ShellRunner(
 ) extends Cancelable {
 
   private val cancelables = new MutableCancelable()
+
   override def cancel(): Unit = {
     cancelables.cancel()
   }
@@ -130,3 +134,38 @@ class ShellRunner(
   }
 
 }
+
+object ShellRunner {
+
+  def runSync(
+      args: List[String],
+      directory: AbsolutePath,
+      redirectErrorOutput: Boolean,
+      additionalEnv: Map[String, String] = Map.empty,
+      processErr: String => Unit = scribe.error(_),
+      propagateError: Boolean = false,
+      maybeJavaHome: Option[String]
+  ): Option[String] = {
+
+    val sbOut = new StringBuilder()
+    val env = additionalEnv ++ maybeJavaHome.map("JAVA_HOME" -> _).toMap
+    val ps = SystemProcess.run(
+      args,
+      directory,
+      redirectErrorOutput,
+      env,
+      Some(s => {
+        sbOut.append(s)
+        sbOut.append(Properties.lineSeparator)
+      }),
+      Some(processErr),
+      propagateError
+    )
+
+    val exit = Await.result(ps.complete, 10 second)
+
+    if (exit == 0) {
+      Some(sbOut.toString())
+    } else None
+  }
+}

metals/src/main/scala/scala/meta/internal/metals/JavaInteractiveSemanticdb.scala

@@ -11,6 +11,7 @@ import scala.util.Properties
 import scala.util.Try
 import scala.util.control.NonFatal
 
+import scala.meta.internal.builds.ShellRunner
 import scala.meta.internal.io.FileIO
 import scala.meta.internal.metals.MetalsEnrichments._
 import scala.meta.internal.mtags.MD5
@@ -180,7 +181,8 @@ object JavaInteractiveSemanticdb {
   def create(
       javaHome: AbsolutePath,
       workspace: AbsolutePath,
-      buildTargets: BuildTargets
+      buildTargets: BuildTargets,
+      jdkVersion: JdkVersion
   ): Option[JavaInteractiveSemanticdb] = {
 
     def pathToJavac(p: AbsolutePath): AbsolutePath = {
@@ -197,22 +199,21 @@ object JavaInteractiveSemanticdb {
 
     val javac = pathToJavac(jdkHome)
 
-    JdkVersion.getJavaVersionFromJavaHome(jdkHome) match {
-      case Some(version) if javac.exists =>
-        val pluginJars = Embedded.downloadSemanticdbJavac
-        val instance = new JavaInteractiveSemanticdb(
-          javac,
-          version,
-          pluginJars,
-          workspace,
-          buildTargets
-        )
-        Some(instance)
-      case value =>
-        scribe.warn(
-          s"Can't instantiate JavaInteractiveSemanticdb (version: ${value}, jdkHome: ${jdkHome}, javac exists: ${javac.exists})"
-        )
-        None
+    if (javac.exists) {
+      val pluginJars = Embedded.downloadSemanticdbJavac
+      val instance = new JavaInteractiveSemanticdb(
+        javac,
+        jdkVersion,
+        pluginJars,
+        workspace,
+        buildTargets
+      )
+      Some(instance)
+    } else {
+      scribe.warn(
+        s"Can't instantiate JavaInteractiveSemanticdb (version: ${jdkVersion}, jdkHome: ${jdkHome}, javac exists: ${javac.exists})"
+      )
+      None
     }
   }
 
@@ -227,38 +228,51 @@ case class JdkVersion(
 
 object JdkVersion {
 
-  def getJavaVersionFromJavaHome(
-      javaHome: AbsolutePath
+  def maybeJdkVersionFromJavaHome(
+      maybeJavaHome: Option[AbsolutePath]
   ): Option[JdkVersion] = {
-
-    def fromReleaseFile: Option[JdkVersion] = {
-      val releaseFile = javaHome.resolve("release")
-      if (releaseFile.exists) {
-        val properties = ConfigFactory.parseFile(
-          releaseFile.toFile,
-          ConfigParseOptions.defaults().setSyntax(ConfigSyntax.PROPERTIES)
-        )
-        try {
-          val version = properties
-            .getString("JAVA_VERSION")
-            .stripPrefix("\"")
-            .stripSuffix("\"")
-          JdkVersion.parse(version)
-        } catch {
-          case NonFatal(e) =>
-            scribe.error("Failed to read jdk version from `release` file", e)
-            None
-        }
-      } else None
+    maybeJavaHome.flatMap { javaHome =>
+      fromReleaseFile(javaHome).orElse {
+        fromShell(javaHome)
+      }
     }
+  }
 
-    def jdk8Fallback: Option[JdkVersion] = {
-      val rtJar = javaHome.resolve("jre").resolve("lib").resolve("rt.jar")
-      if (rtJar.exists) Some(JdkVersion(8))
-      else None
-    }
+  def fromShell(javaHome: AbsolutePath): Option[JdkVersion] = {
+    ShellRunner
+      .runSync(
+        List(javaHome.resolve("bin/java").toString, "-version"),
+        javaHome,
+        redirectErrorOutput = true,
+        maybeJavaHome = Some(javaHome.toString())
+      )
+      .flatMap { javaVersionResponse =>
+        "\\d+\\.\\d+\\.\\d+".r
+          .findFirstIn(javaVersionResponse)
+          .flatMap(JdkVersion.parse)
+      }
+  }
+
+  def fromReleaseFile(javaHome: AbsolutePath): Option[JdkVersion] = {
+    val releaseFile = javaHome.resolve("release")
+    if (releaseFile.exists) {
+      val properties = ConfigFactory.parseFile(
+        releaseFile.toFile,
+        ConfigParseOptions.defaults().setSyntax(ConfigSyntax.PROPERTIES)
+      )
+      try {
+        val version = properties
+          .getString("JAVA_VERSION")
+          .stripPrefix("\"")
+          .stripSuffix("\"")
+        JdkVersion.parse(version)
+      } catch {
+        case NonFatal(e) =>
+          scribe.error("Failed to read jdk version from `release` file", e)
+          None
+      }
+    } else None
 
-    fromReleaseFile.orElse(jdk8Fallback)
   }
 
   def parse(v: String): Option[JdkVersion] = {

metals/src/main/scala/scala/meta/internal/metals/MetalsLanguageServer.scala

@@ -389,15 +389,24 @@ class MetalsLanguageServer(
           workspace,
           fingerprints
         )
-        val javaInteractiveSemanticdb = {
-          val optJavaHome =
-            (userConfig.javaHome orElse JdkSources.defaultJavaHome)
-              .map(AbsolutePath(_))
 
-          optJavaHome.flatMap(
-            JavaInteractiveSemanticdb.create(_, workspace, buildTargets)
-          )
-        }
+        val optJavaHome =
+          (userConfig.javaHome orElse JdkSources.defaultJavaHome)
+            .map(AbsolutePath(_))
+        val maybeJdkVersion: Option[JdkVersion] =
+          JdkVersion.maybeJdkVersionFromJavaHome(optJavaHome)
+        val javaInteractiveSemanticdb =
+          for {
+            javaHome <- optJavaHome
+            jdkVersion <- maybeJdkVersion
+            javaSemanticDb <- JavaInteractiveSemanticdb.create(
+              javaHome,
+              workspace,
+              buildTargets,
+              jdkVersion
+            )
+          } yield javaSemanticDb
+
         interactiveSemanticdbs = register(
           new InteractiveSemanticdbs(
             workspace,
@@ -727,7 +736,8 @@ class MetalsLanguageServer(
           tables,
           clientConfig,
           mtagsResolver,
-          () => userConfig.javaHome
+          () => userConfig.javaHome,
+          maybeJdkVersion
         )
 
         fileDecoderProvider = new FileDecoderProvider(

metals/src/main/scala/scala/meta/internal/metals/doctor/Doctor.scala

@@ -22,6 +22,7 @@ import scala.meta.internal.metals.FileDecoderProvider
 import scala.meta.internal.metals.HtmlBuilder
 import scala.meta.internal.metals.Icons
 import scala.meta.internal.metals.JavaTarget
+import scala.meta.internal.metals.JdkVersion
 import scala.meta.internal.metals.Messages.CheckDoctor
 import scala.meta.internal.metals.MetalsEnrichments._
 import scala.meta.internal.metals.MetalsHttpServer
@@ -54,7 +55,8 @@ final class Doctor(
     tables: Tables,
     clientConfig: ClientConfiguration,
     mtagsResolver: MtagsResolver,
-    javaHome: () => Option[String]
+    javaHome: () => Option[String],
+    maybeJDKVersion: Option[JdkVersion]
 )(implicit ec: ExecutionContext) {
   private val isVisible = new AtomicBoolean(false)
   private val hasProblems = new AtomicBoolean(false)
@@ -64,7 +66,8 @@ final class Doctor(
       mtagsResolver,
       currentBuildServer,
       javaHome,
-      () => clientConfig.isTestExplorerProvider()
+      () => clientConfig.isTestExplorerProvider(),
+      maybeJDKVersion
     )
 
   def onVisibilityDidChange(newState: Boolean): Unit = {

metals/src/main/scala/scala/meta/internal/metals/doctor/ProblemResolver.scala

@@ -21,7 +21,8 @@ class ProblemResolver(
     mtagsResolver: MtagsResolver,
     currentBuildServer: () => Option[BspSession],
     javaHome: () => Option[String],
-    isTestExplorerProvider: () => Boolean
+    isTestExplorerProvider: () => Boolean,
+    maybeJDKVersion: Option[JdkVersion]
 ) {
 
   def isUnsupportedBloopVersion(): Boolean = {
@@ -324,7 +325,7 @@ class ProblemResolver(
         target <- scalaTarget
         javaHome <- target.jvmHome
         version <-
-          JdkVersion.getJavaVersionFromJavaHome(javaHome.toAbsolutePath)
+          maybeJDKVersion
       } yield version
 
     val releaseVersion = javaTarget.releaseVersion.flatMap(JdkVersion.parse)

tests/unit/src/test/scala/tests/JdkVersionSuite.scala

@@ -0,0 +1,18 @@
+package tests
+
+import scala.meta.AbsolutePath
+import scala.meta.internal.metals.JdkVersion
+
+import munit.FunSuite
+
+class JdkVersionSuite extends FunSuite {
+  val javaHome: AbsolutePath = AbsolutePath(System.getProperty("java.home"))
+  test("jdk-shell-version") {
+    assertEquals(
+      JdkVersion.fromShell(javaHome),
+      JdkVersion
+        .fromReleaseFile(javaHome)
+        .orElse(JdkVersion.parse(System.getProperty("java.version")))
+    )
+  }
+}

tests/unit/src/test/scala/tests/troubleshoot/ProblemResolverSuite.scala

@@ -4,6 +4,7 @@ import java.nio.file.Files
 import java.nio.file.Paths
 
 import scala.meta.internal.metals.BuildInfo
+import scala.meta.internal.metals.JdkVersion
 import scala.meta.internal.metals.MetalsEnrichments._
 import scala.meta.internal.metals.ScalaTarget
 import scala.meta.internal.metals.ScalaVersions
@@ -221,7 +222,10 @@ class ProblemResolverSuite extends FunSuite {
         new TestMtagsResolver,
         () => None,
         () => javaHome,
-        () => isTestExplorerProvider
+        () => isTestExplorerProvider,
+        JdkVersion.maybeJdkVersionFromJavaHome(
+          Some(AbsolutePath(System.getProperty("java.home")))
+        )
       )
 
       val target =