Revert "Bump minimum Java version to 17 (LTS)"

This reverts commit ebf9b22f55.

README.md

@@ -2,7 +2,7 @@
 
 ## TL;DR
 
-- Make sure you have Java 17 or higher installed
+- Make sure you have Java 11 or higher installed
 - Download and unpack the [latest release](https://github.com/antville/helma/releases)
 - Invoke `./bin/helma`, resp. `./bin/helma.bat`, depending on your platform
 - Direct your web browser to <http://localhost:8080>
@@ -21,9 +21,9 @@ Although Helma became a Grande Dame of server-side JavaScript already decades ag
 
 ## System Requirements
 
-You need a Java virtual machine version 17 or higher to run Helma.
+You need a Java virtual machine version 11 or higher to run Helma.
 
-Please consult the documentation of your platform on how to obtain and install Java.
+Please consult the documentation of your platform how to obtain and install Java.
 
 You also can directly download a [Java runtime or development kit](https://www.oracle.com/java/technologies/javase-downloads.html#javasejdk) from Oracle.
 

build.gradle

@@ -18,8 +18,8 @@ allprojects {
   apply plugin: 'java'
 
   compileJava {
-    sourceCompatibility = JavaVersion.VERSION_17
-    targetCompatibility = JavaVersion.VERSION_17
+    sourceCompatibility = JavaVersion.VERSION_11
+    targetCompatibility = JavaVersion.VERSION_11
   }
 
   repositories {