[JOHNZON-407] fix NPE in JsonArrayBuilderImpl

(cherry picked from commit 06caf92)

Author: jungm

johnzon-core/src/main/java/org/apache/johnzon/core/JsonArrayBuilderImpl.java

@@ -57,13 +57,13 @@ public JsonArrayBuilderImpl(final Collection<?> initialData, final BufferStrateg
                                 final RejectDuplicateKeysMode rejectDuplicateKeysMode, final JsonProviderImpl jsonProvider) {
         this.bufferProvider = provider;
         this.rejectDuplicateKeysMode = rejectDuplicateKeysMode;
+        this.jsonProvider = jsonProvider;
         this.tmpList = new ArrayList<>();
         if (!initialData.isEmpty()) {
             for (Object initialValue : initialData) {
                 add(initialValue);
             }
         }
-        this.jsonProvider = jsonProvider;
     }
 
     @Override

johnzon-core/src/test/java/org/apache/johnzon/core/JsonArrayBuilderImplTest.java

@@ -202,4 +202,17 @@ public void testCreateArrayBuilderWithCollectionInitialData() {
         JsonArray jsonArray2 = otherBuilder.build();
         Assert.assertEquals("[\"a\",\"b\",\"c\",\"d\"]", jsonArray2.toString());
     }
+
+    /**
+     * Testcase for <a href="https://issues.apache.org/jira/browse/JOHNZON-407">JOHNZON-407</a>
+     */
+    @Test
+    public void issue407() {
+        Collection<Object> initialData = new ArrayList<>();
+        initialData.add(BigDecimal.ONE);
+        initialData.add(BigInteger.ONE);
+
+        // This must not throw an exception
+        Json.createArrayBuilder(initialData).build();
+    }
 }