Update minimum Java version in readme to 11

BUILD.md

@@ -2,7 +2,7 @@
 
 #### Required tools for building the project
 
-* Java Development Kit, version 8 or higher (adoptopenjdk.net or www.graalvm.org)
+* Java Development Kit, version 11 or higher (adoptopenjdk.net or www.graalvm.org)
 * NSIS (nsis.sourceforge.io)
 * Maven (no need for manual installation if using Eclipse)
 
@@ -18,7 +18,7 @@ All other tools and dependencies will be downloaded during build process by Mave
 #### Steps to build using Eclipse
 
 1. Import the projects "SimSystem", "SimTools", "Simulator" and "Simulator-build" into a new workspace.
-2. Set for better compatibility in workspace Preferences>Java>Compiler>JDK Compliance>Compiler compliance level to "1.8" (all higher versions are also supported).
+2. Set for better compatibility in workspace Preferences>Java>Compiler>JDK Compliance>Compiler compliance level to "11" (all higher versions are also supported).
 3. To avoid "Info" level problem messages, set in Preferences>Java>Compiler>Javadoc all dropdowns from "Ignore" to "Info" and in Preferences>Java>Compiler>Error/Warnings in the section "Potential programming problems" the entry "Potential resource leak" from "Ignore" to "Info".
 4. Run target "downloadLanguageTools" in Ant file Simulator/language/ant-language.xml to get tools for updating languages and installers.
 5. Run Maven goals "clean" and "install" on Simulator-build/pom.xml.

README.md

@@ -22,7 +22,7 @@ The Mini Call Center Simulator is mainly used for teaching purposes. In the Mini
 
 The Windows version can be installed with or without admin rights. The zip file version can be used on any platform without installation.
 
-* System requirements: [Java 8 or higher](https://adoptopenjdk.net/ "Download Java from adoptopenjdk.net")
+* System requirements: [Java 11 or higher](https://adoptopenjdk.net/ "Download Java from adoptopenjdk.net")
 * License: [Apache License 2.0](https://opensource.org/licenses/Apache-2.0) (for Mini Callcenter Simulator, the used libraries are partly subject to different open source licenses)
 
 ## Literature (in German)

README_de.md

@@ -22,7 +22,7 @@ Der Mini Callcenter Simulator dient im Wesentlichen zu Lehrzwecken. Im Mini Call
 
 Die Windows-Version kann sowohl mit als auch ohne Admin-Rechte installiert werden. Die zip-Datei-Variante kann auf jeder Plattform ohne Installation verwendet werden.
 
-* Systemvoraussetzung: [Java 8 oder höher](https://adoptopenjdk.net/ "Java von adoptopenjdk.net herunterladen")
+* Systemvoraussetzung: [Java 11 oder höher](https://adoptopenjdk.net/ "Java von adoptopenjdk.net herunterladen")
 * Lizenz: [Apache License 2.0](https://opensource.org/licenses/Apache-2.0) (für den Mini Callcenter Simulator, die verwendeten Bibliotheken unterliegen zum Teil abweichenden Opensource-Lizenzen)
 
 ## Literatur

README_en.md

@@ -22,7 +22,7 @@ The Mini Call Center Simulator is mainly used for teaching purposes. In the Mini
 
 The Windows version can be installed with or without admin rights. The zip file version can be used on any platform without installation.
 
-* System requirements: [Java 8 or higher](https://adoptopenjdk.net/ "Download Java from adoptopenjdk.net")
+* System requirements: [Java 11 or higher](https://adoptopenjdk.net/ "Download Java from adoptopenjdk.net")
 * License: [Apache License 2.0](https://opensource.org/licenses/Apache-2.0) (for Mini Callcenter Simulator, the used libraries are partly subject to different open source licenses)
 
 ## Literature (in German)