diff --git a/johnzon-jsonb/src/main/java/org/apache/johnzon/jsonb/JohnzonBuilder.java b/johnzon-jsonb/src/main/java/org/apache/johnzon/jsonb/JohnzonBuilder.java
index 278e814..28c85b8 100644
--- a/johnzon-jsonb/src/main/java/org/apache/johnzon/jsonb/JohnzonBuilder.java
+++ b/johnzon-jsonb/src/main/java/org/apache/johnzon/jsonb/JohnzonBuilder.java
@@ -56,6 +56,8 @@
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
+import java.math.BigDecimal;
+import java.math.BigInteger;
 import java.nio.charset.StandardCharsets;
 import java.util.*;
 import java.util.concurrent.atomic.AtomicReference;
@@ -234,6 +236,10 @@
                         Integer.parseInt(it.toString()))
                 .ifPresent(builder::setSnippetMaxLength);
 
+        // drop johnzon-mapper BigInteger/BigDecimal built in adapters to not serialize those types as JsonString. See JSON-B spec 3.4.1
+        builder.getAdapters().remove(new AdapterKey(BigDecimal.class, String.class));
+        builder.getAdapters().remove(new AdapterKey(BigInteger.class, String.class));
+
         // user adapters
         final Types types = new Types();
 
diff --git a/johnzon-jsonb/src/test/java/org/apache/johnzon/jsonb/JsonbTypesTest.java b/johnzon-jsonb/src/test/java/org/apache/johnzon/jsonb/JsonbTypesTest.java
index 089f99b..49e4c25 100644
--- a/johnzon-jsonb/src/test/java/org/apache/johnzon/jsonb/JsonbTypesTest.java
+++ b/johnzon-jsonb/src/test/java/org/apache/johnzon/jsonb/JsonbTypesTest.java
@@ -21,6 +21,8 @@
 import static org.junit.Assert.assertEquals;
 
 import java.io.StringReader;
+import java.math.BigDecimal;
+import java.math.BigInteger;
 import java.net.URI;
 import java.net.URL;
 import java.time.Duration;
@@ -63,7 +65,8 @@
         final LocalDate localDate = LocalDate.of(2015, 1, 1);
         final LocalTime localTime = LocalTime.of(1, 2, 3);
         final LocalDateTime localDateTime = LocalDateTime.of(2015, 1, 1, 1, 1);
-        final String expected = "{\"calendar\":\"2015-01-01T01:01:00Z[UTC]\",\"date\":\"2015-01-01T01:01:00Z[UTC]\"," +
+        final String expected = "{\"bigDecimal\":1.5,\"bigInteger\":1," +
+                "\"calendar\":\"2015-01-01T01:01:00Z[UTC]\",\"date\":\"2015-01-01T01:01:00Z[UTC]\"," +
                 "\"duration\":\"PT30S\",\"gregorianCalendar\":\"2015-01-01T01:01:00Z[UTC]\"," +
                 "\"instant\":\"2015-01-01T00:00:00Z\",\"localDate\":\"2015-01-01\"," +
                 "\"localDateTime\":\"2015-01-01T01:01\",\"localTime\":\"01:02:03\"," +
@@ -97,6 +100,8 @@
         assertEquals(TimeUnit.DAYS.toMillis(localDate.toEpochDay()), types.instant.toEpochMilli());
         assertEquals(Duration.of(30, ChronoUnit.SECONDS), types.duration);
         assertEquals(Period.of(0, 1, 10), types.period);
+        assertEquals(BigInteger.valueOf(1), types.bigInteger);
+        assertEquals(BigDecimal.valueOf(1.5), types.bigDecimal);
 
         assertEquals(expected, jsonb.toJson(types));
 
@@ -172,6 +177,8 @@
         private LocalDate localDate;
         private OffsetDateTime offsetDateTime;
         private OffsetTime offsetTime;
+        private BigInteger bigInteger;
+        private BigDecimal bigDecimal;
 
         public LocalTime getLocalTime() {
             return localTime;
@@ -341,6 +348,22 @@
             this.offsetTime = offsetTime;
         }
 
+        public BigInteger getBigInteger() {
+            return bigInteger;
+        }
+
+        public void setBigInteger(BigInteger bigInteger) {
+            this.bigInteger = bigInteger;
+        }
+
+        public BigDecimal getBigDecimal() {
+            return bigDecimal;
+        }
+
+        public void setBigDecimal(BigDecimal bigDecimal) {
+            this.bigDecimal = bigDecimal;
+        }
+
         @Override
         public boolean equals(final Object o) {
             if (this == o) {
@@ -369,7 +392,9 @@
                 Objects.equals(localDateTime, types.localDateTime) &&
                 Objects.equals(localDate, types.localDate) &&
                 Objects.equals(offsetDateTime, types.offsetDateTime) &&
-                Objects.equals(offsetTime, types.offsetTime);
+                Objects.equals(offsetTime, types.offsetTime) &&
+                Objects.equals(bigInteger, types.bigInteger) &&
+                Objects.equals(bigDecimal, types.bigDecimal);
         }
 
         @Override
@@ -377,7 +402,7 @@
             return Objects.hash(
                 url, uri, optionalString, optionalInt, optionalLong, optionalDouble, date,
                 calendar, gregorianCalendar, timeZone, zoneId, zoneOffset, simpleTimeZone, instant, duration,
-                period, localDateTime, localDate, offsetDateTime, offsetTime);
+                period, localDateTime, localDate, offsetDateTime, offsetTime, bigInteger, bigDecimal);
         }
     }
 
diff --git a/johnzon-mapper/src/main/java/org/apache/johnzon/mapper/map/LazyConverterMap.java b/johnzon-mapper/src/main/java/org/apache/johnzon/mapper/map/LazyConverterMap.java
index f1a4e42..9c12067 100644
--- a/johnzon-mapper/src/main/java/org/apache/johnzon/mapper/map/LazyConverterMap.java
+++ b/johnzon-mapper/src/main/java/org/apache/johnzon/mapper/map/LazyConverterMap.java
@@ -55,6 +55,7 @@
 import java.util.Calendar;
 import java.util.Date;
 import java.util.GregorianCalendar;
+import java.util.List;
 import java.util.Locale;
 import java.util.Objects;
 import java.util.Set;
@@ -63,6 +64,7 @@
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Function;
+import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 import static java.time.temporal.ChronoField.DAY_OF_MONTH;
@@ -93,6 +95,13 @@
     private boolean useShortISO8601Format = true;
     private DateTimeFormatter dateTimeFormatter;
 
+    private List<AdapterKey> builtInAdapterKeys = Stream.of(Date.class, URI.class, URL.class, Class.class, String.class,
+                    BigDecimal.class, BigInteger.class, Locale.class, Period.class, Duration.class, Calendar.class, GregorianCalendar.class,
+                    TimeZone.class, ZoneId.class, ZoneOffset.class, SimpleTimeZone.class, Instant.class, LocalDateTime.class, LocalDate.class,
+                    ZonedDateTime.class, OffsetDateTime.class, OffsetTime.class, LocalTime.class)
+            .map(it -> new AdapterKey(it, String.class, true))
+            .collect(Collectors.toList());
+
     public void setUseShortISO8601Format(final boolean useShortISO8601Format) {
         this.useShortISO8601Format = useShortISO8601Format;
     }
@@ -102,6 +111,15 @@
     }
 
     @Override
+    public Adapter<?, ?> remove(Object key) {
+        if (key instanceof AdapterKey) {
+            builtInAdapterKeys.remove(key);
+        }
+
+        return super.remove(key);
+    }
+
+    @Override
     public Adapter<?, ?> get(final Object key) {
         final Adapter<?, ?> found = super.get(key);
         if (found == NO_ADAPTER) {
@@ -112,7 +130,7 @@
                 return null;
             }
             final AdapterKey k = AdapterKey.class.cast(key);
-            if (k.getTo() == String.class) {
+            if (builtInAdapterKeys.contains(k)) {
                 final Adapter<?, ?> adapter = doLazyLookup(k);
                 if (adapter != null) {
                     return adapter;
@@ -132,14 +150,8 @@
     }
 
     public Set<AdapterKey> adapterKeys() {
-        return Stream.concat(
-                super.keySet().stream()
-                        .filter(it -> super.get(it) != NO_ADAPTER),
-                Stream.of(Date.class, URI.class, URL.class, Class.class, String.class, BigDecimal.class, BigInteger.class,
-                        Locale.class, Period.class, Duration.class, Calendar.class, GregorianCalendar.class, TimeZone.class,
-                        ZoneId.class, ZoneOffset.class, SimpleTimeZone.class, Instant.class, LocalDateTime.class, LocalDate.class,
-                        ZonedDateTime.class, OffsetDateTime.class, OffsetTime.class)
-                        .map(it -> new AdapterKey(it, String.class, true)))
+        return Stream.concat(super.keySet().stream(), builtInAdapterKeys.stream())
+                .filter(it -> super.get(it) != NO_ADAPTER)
                 .collect(toSet());
     }
 
diff --git a/pom.xml b/pom.xml
index 0828a5b..baf9653 100644
--- a/pom.xml
+++ b/pom.xml
@@ -347,7 +347,7 @@
                   <property name="ignorePattern" value="@version|@see" />
                 </module>
                 <module name="MethodLength">
-                  <property name="max" value="255" />
+                  <property name="max" value="258" />
                 </module>
                 <module name="ParameterNumber">
                   <property name="max" value="13" />