drop JDK 6 support

.travis.yml

@@ -1,24 +1,13 @@
-# slower instance startup, but needed to work around https://github.com/travis-ci/travis-ci/issues/9713
-sudo: true
-
 language: scala
 
-addons:
-  apt:
-    packages:
-      - openjdk-6-jdk
 scala:
   - 2.11.12
   - 2.12.6
   - 2.13.0-M5
 jdk:
-  - openjdk6
   - oraclejdk8
 env:
   global:
-    # force jdk 8 for sbt due to sonatype droping support for jdk6 on https (TLS 1.0)
-    # https://stackoverflow.com/questions/50824789/why-am-i-getting-received-fatal-alert-protocol-version-or-peer-not-authentic/50824799#50824799
-    - JAVA_HOME: /usr/lib/jvm/java-8-oracle
 
     # PGP_PASSPHRASE
     - secure: "rjetmX9HXoN/scxTCBFCHIUDFryY0Yd29sR6EBrW/2tCOILO09RTCcJB0kPn2YMZ9en8ChTtOpqGF9133f6wZ7/ZINSUt1tNwnbgDlhGbwJW2WFTUEmL7ScdqmgRGa294aVuAfrvJnr+dN92it6ibAB8nThgsjq0LnZREJsKwQ77vvEeATEKutuPLGlrHrmqL7/XCjb2uYz9Xh0sSpyQlKOGt5EN7JzM/Bzyju+RYS9BvnLVV86fey/UWO1DNDa4MU5835akevqvtwN7CpCFxFKgbfc+40bAh7Xc59UnkxP+Lcs2KxJx9heS6RJJiNEx99r59LL2JALyN++yOAS97HEfii4Yc3OK9VRZCNQFW4gNm3VtGNW4EC+LOX/9cUiUNg2J65nY0UF2d6R3vsqiCKaK6C0cm+jIs3fgDHFlB+MiHC/ZECaoPvwzm1AxQMIWyoFFqXuHQk3Ef137G0x1ejneUoGD/PqMbiEAX64+VVvOxgOI2/jyt4hFTEk6JiWVahmk+7oFAsLH1n9J1Y3csMvmo9S0S/Ey9D3bR07hggc8pj/CJPj9gFSfpGEVhroc37T/VlP23EVJgpteovERyeJGC3P7wVWvi1pNNW6iOVENzY1GkHlHkJUI7Q4B+eIW2mh5wi6JyC/DM2lO4z3M2KQkNqQgzIBdm5p/4hezkkA="
@@ -33,13 +22,6 @@ env:
 
 matrix:
   exclude:
-    # > 2.12 requires jdk8
-    - jdk: openjdk6
-      scala: 2.12.6
-
-    - jdk: openjdk6
-      scala: 2.13.0-M5
-
     # ?
     - jdk: oraclejdk8
       scala: 2.11.12
@@ -64,18 +46,6 @@ matrix:
       scala: 2.12.6
       env: TEST_SCALAFMT=true
 
-# | jdk         |   scala   | scala target | scala target version | scalafix test |
-# | ----------- | --------- | ------------ | -------------------- |---------------|
-# |    openjdk6 | 2.11.12   | jvm          |                      |               |
-# |    openjdk6 | 2.11.12   | js           | 0.6.23               |               |
-# |    openjdk6 | 2.11.12   | js           | 1.0.0-M3             |               |
-# |  oraclejdk8 | 2.12.6    | jvm          |                      |               |
-# |  oraclejdk8 | 2.12.6    | js           | 0.6.23               |               |
-# |  oraclejdk8 | 2.12.6    | js           | 1.0.0-M3             |               |
-# |  oraclejdk8 | 2.13.0-M5 | jvm          |                      |               |
-# |  oraclejdk8 | 2.13.0-M5 | js           | 0.6.23               |               |
-# |  oraclejdk8 | 2.12.6    | jvm          |                      |   true        |
-
 before_script:
   - admin/checkCLA.sh
 

build.sbt

@@ -58,23 +58,7 @@ lazy val compat = MultiScalaCrossProject(JSPlatform, JVMPlatform)(
     )
     .jvmSettings(
       OsgiKeys.exportPackage := Seq(s"scala.collection.compat.*;version=${version.value}"),
-      junit,
-      javaHome in Compile := {
-        val oldValue = (javaHome in Compile).value
-        val isOnCi   = sys.env.get("CI").isDefined
-
-        if (isOnCi) {
-          // switch back to the jdk set by the build matrix
-          val ciJavaHome =
-            sys.env("TRAVIS_JDK_VERSION") match {
-              case "openjdk6"   => "/usr/lib/jvm/java-6-openjdk-amd64"
-              case "oraclejdk8" => "/usr/lib/jvm/java-8-oracle"
-            }
-          println(s"using JAVA_HOME: $ciJavaHome")
-          Some(file(ciJavaHome))
-        } else oldValue
-      },
-      javaHome in Test := (javaHome in Compile).value
+      junit
     )
     .jsSettings(
       scalacOptions += {