Update documentation for Java 15

README.MD

@@ -82,7 +82,7 @@ java -jar webgoat-server-8.1.0.jar [--server.port=8080] [--server.address=localh
 java -jar webwolf-8.1.0.jar [--server.port=9090] [--server.address=localhost]
 ```
 
-The latest version of WebGoat needs Java 11 or above. By default WebGoat and WebWolf start on port 8080,9000 and 9090 with the environment variable WEBGOAT_PORT, WEBWOLF_PORT and WEBGOAT_HSQLPORT you can set different values.
+The latest version of WebGoat needs Java 15 or above. By default WebGoat and WebWolf start on port 8080,9000 and 9090 with the environment variable WEBGOAT_PORT, WEBWOLF_PORT and WEBGOAT_HSQLPORT you can set different values.
 ```Shell
 export WEBGOAT_PORT=18080
 export WEBGOAT_HSQLPORT=19001
@@ -97,7 +97,7 @@ Use set in stead of export on Windows cmd.
 
 ### Prerequisites:
 
-* Java 11
+* Java 15
 * Maven > 3.2.1
 * Your favorite IDE
 * Git, or Git support in your IDE

pom.xml

@@ -189,9 +189,10 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
+                <version>${maven-compiler-plugin.version}</version>
                 <configuration>
-                    <source>11</source>
-                    <target>11</target>
+                    <source>15</source>
+                    <target>15</target>
                     <encoding>UTF-8</encoding>
                 </configuration>
             </plugin>
@@ -213,7 +214,7 @@
                 <artifactId>maven-pmd-plugin</artifactId>
                 <version>3.14.0</version>
                 <configuration>
-                    <targetJdk>11</targetJdk>
+                    <targetJdk>15</targetJdk>
                     <failurePriority>1</failurePriority><!-- 5 means fail even on the lowest priority, 0 means never fail -->
                     <rulesets>
                         <!--suppress UnresolvedMavenProperty -->