build: switch default java version to 17 (#159)

Author: ndr-brt

build.gradle.kts

@@ -33,23 +33,12 @@ allprojects {
         }
     }
 
-    tasks.withType<Test> {
-        useJUnitPlatform()
-        testLogging {
-            showStandardStreams = true
-        }
-    }
-
     // configure checkstyle version
     checkstyle {
         toolVersion = "10.0"
         maxErrors = 0 // does not tolerate errors
     }
 
-    repositories {
-        mavenCentral()
-    }
-
     // let's not generate any reports because that is done from within the Github Actions workflow
     tasks.withType<Checkstyle> {
         reports {

plugins/edc-build/src/main/java/org/eclipse/edc/plugins/edcbuild/conventions/JavaConvention.java

@@ -27,7 +27,7 @@
  */
 class JavaConvention implements EdcConvention {
 
-    private static final int DEFAULT_JAVA_VERSION = 11;
+    private static final int DEFAULT_JAVA_VERSION = 17;
 
     @Override
     public void apply(Project target) {
@@ -53,4 +53,5 @@ public void apply(Project target) {
         javaPluginExt.withJavadocJar();
         javaPluginExt.withSourcesJar();
     }
+
 }