[567050] Cannot Setup Xtext with 2020-09 Eclipse installer

https://bugs.eclipse.org/bugs/show_bug.cgi?id=567050
diff --git a/releng/org.eclipse.oomph.parent/pom.xml b/releng/org.eclipse.oomph.parent/pom.xml
index d7f7b12..9206c5d 100644
--- a/releng/org.eclipse.oomph.parent/pom.xml
+++ b/releng/org.eclipse.oomph.parent/pom.xml
@@ -145,9 +145,9 @@
                 </artifact>
               </target>
               <!--  This is needed for Tycho 2.0.0, but breaks 1.7.0 because the compiler source/target levels are not set properly.
-              <executionEnvironment>org.eclipse.justj.openjdk.hotspot.jre.minimal-14</executionEnvironment>
+              <executionEnvironment>org.eclipse.justj.openjdk.hotspot.jre.minimal-15</executionEnvironment>
               -->
-              <executionEnvironmentDefault>org.eclipse.justj.openjdk.hotspot.jre.minimal-14</executionEnvironmentDefault>
+              <executionEnvironmentDefault>org.eclipse.justj.openjdk.hotspot.jre.minimal-15</executionEnvironmentDefault>
               <includePackedArtifacts>true</includePackedArtifacts>
               <environments>
                 <environment>
diff --git a/releng/org.eclipse.oomph.parent/tp/org.eclipse.oomph.tp.target b/releng/org.eclipse.oomph.parent/tp/org.eclipse.oomph.tp.target
index b7b58e8..d61323e 100644
--- a/releng/org.eclipse.oomph.parent/tp/org.eclipse.oomph.tp.target
+++ b/releng/org.eclipse.oomph.parent/tp/org.eclipse.oomph.tp.target
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <?pde version="3.8"?>
-<target name="Generated from Oomph" sequenceNumber="61">
+<target name="Generated from Oomph" sequenceNumber="62">
   <locations>
     <location includeAllPlatforms="false" includeConfigurePhase="true" includeMode="planner" includeSource="true" type="InstallableUnit">
       <unit id="org.eclipse.egit.feature.group" version="0.0.0"/>
@@ -27,7 +27,7 @@
       <repository location="http://download.eclipse.org/technology/swtbot/snapshots"/>
       <repository location="http://download.eclipse.org/webtools/repository/latest"/>
       <repository location="http://download.eclipse.org/justj/jres/14/updates/release/14.0.2"/>
-      <repository location="http://download.eclipse.org/eclipse/updates/4.17/R-4.17-202009021800"/>
+      <repository location="http://download.eclipse.org/justj/jres/15/updates/milestone/latest"/>
     </location>
   </locations>
 </target>