JCR-5018: bump up minimal Java version to 11

README.txt

@@ -19,7 +19,7 @@ You can build Jackrabbit like this:
 
     mvn clean install
 
-You need Maven 3 (or higher) with Java 8 (or higher) for the
+You need Maven 3 (or higher) with Java 11 (or higher) for the
 build. For more instructions, please see the documentation at:
 
    http://jackrabbit.apache.org/building-jackrabbit.html

jackrabbit-parent/pom.xml

@@ -64,8 +64,10 @@
     <slf4j.api.version>1.7.36</slf4j.api.version>
     <slf4j.version>1.7.36</slf4j.version> <!-- sync with logback version -->
     <logback.version>1.2.11</logback.version>
-    <java.version>1.8</java.version>
-    <java.version.signature>java18</java.version.signature>
+    <java.version>11</java.version>
+    <maven.compiler.release>${java.version}</maven.compiler.release>
+    <maven.compiler.target>${java.version}</maven.compiler.target>
+    <minimalJavaBuildVersion>${java.version}</minimalJavaBuildVersion>
     <skip.coverage>true</skip.coverage>
     <minimum.line.coverage>0.0</minimum.line.coverage>
     <minimum.branch.coverage>0.0</minimum.branch.coverage>
@@ -204,29 +206,10 @@
       <plugin>
         <artifactId>maven-compiler-plugin</artifactId>
         <configuration>
-          <target>${java.version}</target>
-          <source>${java.version}</source>
-        </configuration>
-      </plugin>
-      <plugin>
-        <groupId>org.codehaus.mojo</groupId>
-        <artifactId>animal-sniffer-maven-plugin</artifactId>
-        <version>1.23</version>
-        <configuration>
-          <signature>
-            <groupId>org.codehaus.mojo.signature</groupId>
-            <artifactId>${java.version.signature}</artifactId>
-            <version>1.0</version>
-          </signature>
+          <compilerArgs>
+            <arg>-Xpkginfo:always</arg>
+          </compilerArgs>
         </configuration>
-        <executions>
-          <execution>
-            <phase>compile</phase>
-            <goals>
-              <goal>check</goal>
-            </goals>
-          </execution>
-        </executions>
       </plugin>
       <!-- Generate aggregate Javadocs -->
       <plugin>