diff --git a/io/src/main/scala/sbt/io/IO.scala b/io/src/main/scala/sbt/io/IO.scala
index 5c0e1146..69b9d40b 100644
--- a/io/src/main/scala/sbt/io/IO.scala
+++ b/io/src/main/scala/sbt/io/IO.scala
@@ -148,19 +148,16 @@ object IO {
               case "jar" =>
                 val path = url.getPath
                 val end = path.indexOf('!')
-                new URL(
+                new URI(
                   if (end == -1) path
                   else path.substring(0, end)
-                )
+                ).toURL
               case "jrt" =>
                 val path = url.getPath
                 val end = path.indexOf('/', 1)
-                new URL(
-                  "jrt",
-                  null,
-                  if (end == -1) path
-                  else path.substring(0, end)
-                )
+                new URI(
+                  s"jrt://${if (end == -1) path else path.substring(0, end)}"
+                ).toURL
               case _ => url
             }
         )
diff --git a/io/src/main/scala/sbt/io/syntax.scala b/io/src/main/scala/sbt/io/syntax.scala
index d25e5dc8..a23bb573 100644
--- a/io/src/main/scala/sbt/io/syntax.scala
+++ b/io/src/main/scala/sbt/io/syntax.scala
@@ -36,7 +36,7 @@ object syntax extends IOSyntax0 {
 
   def uri(s: String): URI = new URI(s)
   def file(s: String): File = new File(s)
-  def url(s: String): URL = new URL(s)
+  def url(s: String): URL = uri(s).toURL
 
   implicit def fileToRichFile(file: File): RichFile = new RichFile(file)
   implicit def filesToFinder(cc: Traversable[File]): PathFinder = PathFinder.strict(cc)