diff --git a/java/concurrency/workers/build.gradle.kts b/java/concurrency/workers/build.gradle.kts
index 2168f1e3..89926e80 100644
--- a/java/concurrency/workers/build.gradle.kts
+++ b/java/concurrency/workers/build.gradle.kts
@@ -10,7 +10,6 @@ tasks.javadoc {
 
 repositories {
     mavenCentral()
-    jcenter()
 }
 
 dependencies {
diff --git a/java/lambdas/utilities-for-lists-and-maps/src/main/java/it/unibo/oop/lab/lambda/LambdaUtilities.java b/java/lambdas/utilities-for-lists-and-maps/src/main/java/it/unibo/oop/lab/lambda/LambdaUtilities.java
index 7a2cb196..dd6e978c 100644
--- a/java/lambdas/utilities-for-lists-and-maps/src/main/java/it/unibo/oop/lab/lambda/LambdaUtilities.java
+++ b/java/lambdas/utilities-for-lists-and-maps/src/main/java/it/unibo/oop/lab/lambda/LambdaUtilities.java
@@ -51,6 +51,7 @@ public static <T> List<T> dup(final List<T> list, final UnaryOperator<T> op) {
     /**
      * @param list
      *            input list
+
      * @param pre
      *            predicate to execute
      * @param <T>
diff --git a/java/streams/utilities-for-music-model/build.gradle.kts b/java/streams/utilities-for-music-model/build.gradle.kts
index 2168f1e3..89926e80 100644
--- a/java/streams/utilities-for-music-model/build.gradle.kts
+++ b/java/streams/utilities-for-music-model/build.gradle.kts
@@ -10,7 +10,6 @@ tasks.javadoc {
 
 repositories {
     mavenCentral()
-    jcenter()
 }
 
 dependencies {
diff --git a/java/streams/utilities-for-music-model/src/main/java/it/unibo/oop/lab/streams/MusicGroupImpl.java b/java/streams/utilities-for-music-model/src/main/java/it/unibo/oop/lab/streams/MusicGroupImpl.java
index cd201b4b..8665f903 100644
--- a/java/streams/utilities-for-music-model/src/main/java/it/unibo/oop/lab/streams/MusicGroupImpl.java
+++ b/java/streams/utilities-for-music-model/src/main/java/it/unibo/oop/lab/streams/MusicGroupImpl.java
@@ -9,7 +9,6 @@
 import java.util.Set;
 import java.util.Map.Entry;
 import java.util.stream.Collectors;
-import java.util.stream.LongStream;
 import java.util.stream.Stream;
 
 /**
diff --git a/java/streams/utilities-for-music-model/src/test/java/it/unibo/oop/lab/streams/TestMusicGroup.java b/java/streams/utilities-for-music-model/src/test/java/it/unibo/oop/lab/streams/TestMusicGroup.java
index 21198be2..ccbdb73f 100644
--- a/java/streams/utilities-for-music-model/src/test/java/it/unibo/oop/lab/streams/TestMusicGroup.java
+++ b/java/streams/utilities-for-music-model/src/test/java/it/unibo/oop/lab/streams/TestMusicGroup.java
@@ -68,16 +68,17 @@ void testAlbumNames() {
      */
     @Test
     void testOrderedSongNames() {
-        final List<String> result = Arrays.asList(new String[] {
-                "Black Dog",
-                "Dazed and Confused",
-                "I Can't Quit You Baby",
-                "Immigrant Song",
-                "Ramble On",
-                "That's the Way",
-                "Travelling Riverside Blues",
-                "When the Levee Breaks",
-                "Whole Lotta Love" });
+        final List<String> result = Arrays.asList(
+            "Black Dog",
+            "Dazed and Confused",
+            "I Can't Quit You Baby",
+            "Immigrant Song",
+            "Ramble On",
+            "That's the Way",
+            "Travelling Riverside Blues",
+            "When the Levee Breaks",
+            "Whole Lotta Love"
+        );
         final List<String> actual = lz.orderedSongNames().collect(toList());
         assertEquals(result, actual);
     }
@@ -87,7 +88,7 @@ void testOrderedSongNames() {
      */
     @Test
     void testAlbumInYear() {
-        final List<String> result = Arrays.asList(new String[] { II, I });
+        final List<String> result = Arrays.asList(II, I);
         final List<String> actual = lz.albumInYear(1969).collect(toList());
         assertEquals(result, actual);
     }
diff --git a/java/streams/utilities-for-text-processing/build.gradle.kts b/java/streams/utilities-for-text-processing/build.gradle.kts
index 2168f1e3..89926e80 100644
--- a/java/streams/utilities-for-text-processing/build.gradle.kts
+++ b/java/streams/utilities-for-text-processing/build.gradle.kts
@@ -10,7 +10,6 @@ tasks.javadoc {
 
 repositories {
     mavenCentral()
-    jcenter()
 }
 
 dependencies {
diff --git a/tests.main.kts b/tests.main.kts
index df0f58fa..f5831fba 100755
--- a/tests.main.kts
+++ b/tests.main.kts
@@ -35,7 +35,7 @@ File("java/inheritance/").inAllDirectories {
     gradle("compileJava")
 }
 
-listOf("collections", "generics", "exceptions", "lambdas").forEach {
+listOf("collections", "generics", "exceptions", "lambdas", "streams").forEach {
     File("java/$it").inAllDirectories {
         val tasks = arrayOf("build") + when (git.currentBranch()) {
             "exercises" -> arrayOf("-x", "test")