diff --git a/app/src/cc/arduino/contributions/libraries/LibraryByTypeComparator.java b/app/src/cc/arduino/contributions/libraries/LibraryByTypeComparator.java
index e74937025..11052ae74 100644
--- a/app/src/cc/arduino/contributions/libraries/LibraryByTypeComparator.java
+++ b/app/src/cc/arduino/contributions/libraries/LibraryByTypeComparator.java
@@ -47,13 +47,17 @@ public class LibraryByTypeComparator implements Comparator<UserLibrary> {
 
   @Override
   public int compare(UserLibrary o1, UserLibrary o2) {
-    if (o1.getTypes() == null) {
+    if (o1.getTypes().isEmpty() && o2.getTypes().isEmpty()) {
+      return 0;
+    }
+    if (o1.getTypes().isEmpty()) {
       return 1;
     }
-    if (o2.getTypes() == null) {
+    if (o2.getTypes().isEmpty()) {
       return -1;
     }
-    return libraryTypeComparator.compare(o1.getTypes().get(0), o2.getTypes().get(0));
+    return libraryTypeComparator.compare(o1.getTypes().get(0),
+                                         o2.getTypes().get(0));
   }
 
 }
diff --git a/app/src/cc/arduino/contributions/libraries/LibraryOfSameTypeComparator.java b/app/src/cc/arduino/contributions/libraries/LibraryOfSameTypeComparator.java
index bf52efa6c..45a42b7b7 100644
--- a/app/src/cc/arduino/contributions/libraries/LibraryOfSameTypeComparator.java
+++ b/app/src/cc/arduino/contributions/libraries/LibraryOfSameTypeComparator.java
@@ -37,10 +37,13 @@ public class LibraryOfSameTypeComparator implements Comparator<UserLibrary> {
 
   @Override
   public int compare(UserLibrary o1, UserLibrary o2) {
-    if (o1.getTypes() == null) {
+    if (o1.getTypes().isEmpty() && o2.getTypes().isEmpty()) {
+      return 0;
+    }
+    if (o1.getTypes().isEmpty()) {
       return 1;
     }
-    if (o2.getTypes() == null) {
+    if (o2.getTypes().isEmpty()) {
       return -1;
     }
     if (!o1.getTypes().get(0).equals(o2.getTypes().get(0))) {
diff --git a/app/src/processing/app/Base.java b/app/src/processing/app/Base.java
index 2d54e26b9..62535c790 100644
--- a/app/src/processing/app/Base.java
+++ b/app/src/processing/app/Base.java
@@ -1193,10 +1193,7 @@ public class Base {
       if (location == Location.IDE_BUILTIN) {
         if (compatible) {
           // only compatible IDE libs are shown
-          boolean retired = false;
-          List<String> types = lib.getTypes();
-          if (types != null) retired = types.contains("Retired");
-          if (retired) {
+          if (lib.getTypes().contains("Retired")) {
             retiredIdeLibs.add(lib);
           } else {
             ideLibs.add(lib);
@@ -1214,7 +1211,7 @@ public class Base {
       } else if (location == Location.SKETCHBOOK) {
         if (compatible) {
           // libraries promoted from sketchbook (behave as builtin)
-          if (lib.getTypes() != null && lib.getTypes().contains("Arduino")
+          if (!lib.getTypes().isEmpty() && lib.getTypes().contains("Arduino")
               && lib.getArchitectures().contains("*")) {
             ideLibs.add(lib);
           } else {
diff --git a/arduino-core/src/cc/arduino/contributions/libraries/LibrariesIndexer.java b/arduino-core/src/cc/arduino/contributions/libraries/LibrariesIndexer.java
index b1266e2b5..c21a8e91b 100644
--- a/arduino-core/src/cc/arduino/contributions/libraries/LibrariesIndexer.java
+++ b/arduino-core/src/cc/arduino/contributions/libraries/LibrariesIndexer.java
@@ -204,11 +204,11 @@ public class LibrariesIndexer {
       }
     }
 
-    if (lib.getTypes() == null && folderDesc.location == Location.SKETCHBOOK) {
+    if (lib.getTypes().isEmpty() && loc == Location.SKETCHBOOK) {
       lib.setTypes(lib.getDeclaredTypes());
     }
 
-    if (lib.getTypes() == null) {
+    if (lib.getTypes().isEmpty()) {
       lib.setTypes(Collections.singletonList("Contributed"));
     }
   }
diff --git a/arduino-core/src/cc/arduino/contributions/libraries/filters/TypePredicate.java b/arduino-core/src/cc/arduino/contributions/libraries/filters/TypePredicate.java
index 36b19a21a..330fc03b3 100644
--- a/arduino-core/src/cc/arduino/contributions/libraries/filters/TypePredicate.java
+++ b/arduino-core/src/cc/arduino/contributions/libraries/filters/TypePredicate.java
@@ -43,7 +43,7 @@ public class TypePredicate implements Predicate<UserLibrary> {
 
   @Override
   public boolean test(UserLibrary input) {
-    return input.getTypes() != null && input.getTypes().contains(type);
+    return input.getTypes().contains(type);
   }
 
 }
diff --git a/arduino-core/src/processing/app/packages/UserLibrary.java b/arduino-core/src/processing/app/packages/UserLibrary.java
index dceeeb41c..c6c2c2ffc 100644
--- a/arduino-core/src/processing/app/packages/UserLibrary.java
+++ b/arduino-core/src/processing/app/packages/UserLibrary.java
@@ -56,7 +56,7 @@ public class UserLibrary {
   private String category;
   private String license;
   private List<String> architectures;
-  private List<String> types;
+  private List<String> types = new ArrayList<>();
   private List<String> declaredTypes;
   private boolean onGoingDevelopment;
   private List<String> includes;