Remove some references to JDK8

TROUBLESHOOTING.md

@@ -46,9 +46,6 @@ apt install openjdk-8-dbg
 # Ubuntu/Debian - Java 11
  apt install openjdk-11-dbg
 
-# On CentOS, RHEL and some other RPM-based distributions - Java 8
-debuginfo-install java-1.8.0-openjdk
-
 # On CentOS, RHEL and some other RPM-based distributions - Java 11
 debuginfo-install java-11-openjdk
 ```

docs/src/main/asciidoc/building-my-first-extension.adoc

@@ -163,8 +163,8 @@ Your extension is a multi-module project. So let's start by checking out the par
     <compiler-plugin.version>3.8.1</compiler-plugin.version><!--2-->
     <failsafe-plugin.version>${surefire-plugin.version}</failsafe-plugin.version>
     <maven.compiler.parameters>true</maven.compiler.parameters>
-    <maven.compiler.source>1.8</maven.compiler.source>
-    <maven.compiler.target>1.8</maven.compiler.target>
+    <maven.compiler.source>11</maven.compiler.source>
+    <maven.compiler.target>11</maven.compiler.target>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
     <quarkus.version>{quarkus-version}</quarkus.version>

extensions/hibernate-orm/pom.xml

@@ -45,27 +45,18 @@
                                     <!--<bundledSignature>jdk-reflection</bundledSignature>-->
 
                                     <!-- All following signatures should be replicated for each target JDK version we intend to support -->
-                                    <bundledSignature>jdk-unsafe-1.8</bundledSignature>
-                                    <bundledSignature>jdk-unsafe-9</bundledSignature>
-                                    <bundledSignature>jdk-unsafe-10</bundledSignature>
                                     <bundledSignature>jdk-unsafe-11</bundledSignature>
                                     <bundledSignature>jdk-unsafe-12</bundledSignature>
                                     <bundledSignature>jdk-unsafe-13</bundledSignature>
                                     <bundledSignature>jdk-unsafe-14</bundledSignature>
                                     <bundledSignature>jdk-unsafe-15</bundledSignature>
 
-                                    <bundledSignature>jdk-deprecated-1.8</bundledSignature>
-                                    <bundledSignature>jdk-deprecated-9</bundledSignature>
-                                    <bundledSignature>jdk-deprecated-10</bundledSignature>
                                     <bundledSignature>jdk-deprecated-11</bundledSignature>
                                     <bundledSignature>jdk-deprecated-12</bundledSignature>
                                     <bundledSignature>jdk-deprecated-13</bundledSignature>
                                     <bundledSignature>jdk-deprecated-14</bundledSignature>
                                     <bundledSignature>jdk-deprecated-15</bundledSignature>
 
-                                    <bundledSignature>jdk-internal-1.8</bundledSignature>
-                                    <bundledSignature>jdk-internal-9</bundledSignature>
-                                    <bundledSignature>jdk-internal-10</bundledSignature>
                                     <bundledSignature>jdk-internal-11</bundledSignature>
                                     <bundledSignature>jdk-internal-12</bundledSignature>
                                     <bundledSignature>jdk-internal-13</bundledSignature>