use java8 compatible api

Author: rochala

presentation-compiler/test/dotty/tools/pc/utils/JdkIndex.scala

@@ -22,7 +22,7 @@ import dotty.tools.dotc.util.SourceFile
 class JdkIndex():
   val jdkSources = JdkSources()
   private val maybeJdkZipFs: Option[FileSystem] =
-    jdkSources.toOption.map(FileSystems.newFileSystem(_, Collections.emptyMap))
+    jdkSources.toOption.map(FileSystems.newFileSystem(_, (null: ClassLoader)))
 
   def search(classfile: String, symbol: Symbol, query: String)(using
       Context
@@ -35,7 +35,8 @@ class JdkIndex():
         .split("$")
         .headOption
         .map(_.stripSuffix("class") ++ "java")
-      content <- Try { Files.readString(fsroot.resolve(javafile)) }.toOption
+      if Files.exists(fsroot.resolve(javafile))
+      content <- Try { String(Files.readAllBytes(fsroot.resolve(javafile))) }.toOption
       virtualFile = SourceFile.virtual(javafile, content)
       untpdTree <- Try { JavaParser(virtualFile).parse() }.toOption
       symbol <- extractSymbolInformation(untpdTree, symbol, query)

presentation-compiler/test/dotty/tools/pc/utils/JdkSources.scala

@@ -47,7 +47,7 @@ object JdkSources:
           // In case java.home points to the JRE instead of the JDK,
           // try to find jdk among its siblings
           Option(javaHome.getParent).toList
-            .flatMap(Files.list(_).toList.asScala)
+            .flatMap(Files.list(_).iterator.asScala)
             .filter(isJdkCandidate)
             .toArray[Path]
             .sortBy(_.filename)

presentation-compiler/test/dotty/tools/pc/utils/PcAssertions.scala

@@ -71,7 +71,7 @@ trait PcAssertions:
     throw error
 
   private def unifyNewlines(str: String): String =
-    str.linesIterator.dropWhile(_.isBlank).mkString("\n").stripTrailing()
+    str.linesIterator.dropWhile(_.trim.isEmpty).mkString("\n").trim
 
   private def addSnippet(description: StringDescription)(snippet: String) =
     description.appendText(System.lineSeparator)