diff --git a/lib/src/main/java/nl/sanderhautvast/json/ser/Mapper.java b/lib/src/main/java/nl/sanderhautvast/json/ser/Mapper.java
index f7de7ac..51dfead 100644
--- a/lib/src/main/java/nl/sanderhautvast/json/ser/Mapper.java
+++ b/lib/src/main/java/nl/sanderhautvast/json/ser/Mapper.java
@@ -31,6 +31,7 @@ public class Mapper {
      * @param type   The class to serialize to json
      * @param mapper the Mapper implementation
      */
+    @SuppressWarnings("unused")
     public static <T> void addMapper(Class<T> type, BaseMapper<T> mapper) {
         mappers.put(type, mapper);
     }
diff --git a/lib/src/test/java/nl/sanderhautvast/json/ser/collections/SetTest.java b/lib/src/test/java/nl/sanderhautvast/json/ser/collections/SetTest.java
index 314f2b2..7d14ddd 100644
--- a/lib/src/test/java/nl/sanderhautvast/json/ser/collections/SetTest.java
+++ b/lib/src/test/java/nl/sanderhautvast/json/ser/collections/SetTest.java
@@ -30,6 +30,7 @@ public class SetTest {
                 || "{\"set\":[\"value1\",\"value2\"]}".equals(jsonString));
     }
 
+    @SuppressWarnings("unused")
     public static class Bean {
         private Set<String> set;
 
diff --git a/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/BooleanPropertyTest.java b/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/BooleanPropertyTest.java
index 1cf99f4..1c4caf3 100644
--- a/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/BooleanPropertyTest.java
+++ b/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/BooleanPropertyTest.java
@@ -24,6 +24,7 @@ public class BooleanPropertyTest {
         assertEquals("{\"data\":true}", Mapper.json(object));
     }
 
+    @SuppressWarnings("unused")
     public static class Bean {
         boolean data;
 
diff --git a/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/BytePropertyTest.java b/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/BytePropertyTest.java
index 8c6c6d6..1c4302e 100644
--- a/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/BytePropertyTest.java
+++ b/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/BytePropertyTest.java
@@ -23,6 +23,7 @@ public class BytePropertyTest {
         assertEquals("{\"data\":1}", Mapper.json(object));
     }
 
+    @SuppressWarnings("unused")
     public static class Bean {
         private byte data;
 
diff --git a/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/CharPropertyTest.java b/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/CharPropertyTest.java
index fae2f4d..dad50e0 100644
--- a/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/CharPropertyTest.java
+++ b/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/CharPropertyTest.java
@@ -23,6 +23,7 @@ public class CharPropertyTest {
         assertEquals("{\"data\":\"a\"}", Mapper.json(object));
     }
 
+    @SuppressWarnings("unused")
     public static class Bean {
         private char data;
 
diff --git a/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/FloatPropertyTest.java b/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/FloatPropertyTest.java
index 88f79bc..f9d39be 100644
--- a/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/FloatPropertyTest.java
+++ b/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/FloatPropertyTest.java
@@ -23,6 +23,7 @@ public class FloatPropertyTest {
         assertEquals("{\"data\":1.0}", Mapper.json(object));
     }
 
+    @SuppressWarnings("unused")
     public static class Bean {
         private float data;
 
diff --git a/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/IntPropertyTest.java b/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/IntPropertyTest.java
index 9c38bcd..5dbdbfb 100644
--- a/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/IntPropertyTest.java
+++ b/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/IntPropertyTest.java
@@ -24,6 +24,7 @@ public class IntPropertyTest {
         assertEquals("{\"data\":1}", Mapper.json(object));
     }
 
+    @SuppressWarnings("unused")
     public static class Bean {
         int data;
 
diff --git a/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/LongPropertyTest.java b/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/LongPropertyTest.java
index a265cdf..f90070e 100644
--- a/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/LongPropertyTest.java
+++ b/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/LongPropertyTest.java
@@ -23,6 +23,7 @@ public class LongPropertyTest {
         assertEquals("{\"data\":1}", Mapper.json(object));
     }
 
+    @SuppressWarnings("unused")
     public static class Bean {
         private long data;
 
diff --git a/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/NullPropertyTest.java b/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/NullPropertyTest.java
index 637c1c0..9eb0918 100644
--- a/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/NullPropertyTest.java
+++ b/lib/src/test/java/nl/sanderhautvast/json/ser/primitives/NullPropertyTest.java
@@ -13,6 +13,7 @@ public class NullPropertyTest {
         assertEquals("{\"data\":null}", Mapper.json(object));
     }
 
+    @SuppressWarnings("unused")
     public static class Bean {
         private String data;