diff --git a/vxquery-core/src/main/java/org/apache/vxquery/functions/builtin-operators.xml b/vxquery-core/src/main/java/org/apache/vxquery/functions/builtin-operators.xml
index e89d619..e28d405 100644
--- a/vxquery-core/src/main/java/org/apache/vxquery/functions/builtin-operators.xml
+++ b/vxquery-core/src/main/java/org/apache/vxquery/functions/builtin-operators.xml
@@ -856,14 +856,14 @@
     <!-- opext:array-constructor($expression as item()*) as array() -->
     <operator name="opext:array-constructor">
         <param name="expression" type="item()*"/>
-        <return type="item()"/>
+        <return type="array()"/>
         <runtime type="scalar" class="org.apache.vxquery.runtime.functions.jsonitem.ArrayConstructorScalarEvaluatorFactory"/>
     </operator>
 
     <!-- opext:object-constructor($expression as item()*) as object() -->
     <operator name="opext:object-constructor">
         <param name="expression" type="item()*"/>
-        <return type="item()"/>
+        <return type="object()"/>
         <runtime type="scalar" class="org.apache.vxquery.runtime.functions.jsonitem.ObjectConstructorScalarEvaluatorFactory"/>
     </operator>
 
diff --git a/vxquery-core/src/main/java/org/apache/vxquery/types/AbstractJsonItemType.java b/vxquery-core/src/main/java/org/apache/vxquery/types/AbstractJsonItemType.java
new file mode 100644
index 0000000..c890d4d
--- /dev/null
+++ b/vxquery-core/src/main/java/org/apache/vxquery/types/AbstractJsonItemType.java
@@ -0,0 +1,26 @@
+/*
+* Licensed to the Apache Software Foundation (ASF) under one or more
+* contributor license agreements.  See the NOTICE file distributed with
+* this work for additional information regarding copyright ownership.
+* The ASF licenses this file to You under the Apache License, Version 2.0
+* (the "License"); you may not use this file except in compliance with
+* the License.  You may obtain a copy of the License at
+*
+*     http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+package org.apache.vxquery.types;
+
+abstract class AbstractJsonItemType implements JsonItemType {
+    private static final long serialVersionUID = 1L;
+
+    @Override
+    public final boolean isAtomicType() {
+        return false;
+    }
+}
diff --git a/vxquery-core/src/main/java/org/apache/vxquery/types/AnyJsonItemType.java b/vxquery-core/src/main/java/org/apache/vxquery/types/AnyJsonItemType.java
new file mode 100644
index 0000000..6b367ba
--- /dev/null
+++ b/vxquery-core/src/main/java/org/apache/vxquery/types/AnyJsonItemType.java
@@ -0,0 +1,45 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.vxquery.types;
+
+public final class AnyJsonItemType extends AbstractJsonItemType {
+    private static final long serialVersionUID = 1L;
+    public static final AnyJsonItemType INSTANCE = new AnyJsonItemType();
+
+    private AnyJsonItemType() {
+    }
+
+    @Override
+    public String toString() {
+        return "json-item";
+    }
+
+    @Override
+    public int hashCode() {
+        return AnyJsonItemType.class.hashCode();
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        return other instanceof AnyJsonItemType;
+    }
+
+    @Override
+    public JsonItemKind getJsonItemKind() {
+        return JsonItemKind.ANY;
+    }
+}
diff --git a/vxquery-core/src/main/java/org/apache/vxquery/types/ArrayType.java b/vxquery-core/src/main/java/org/apache/vxquery/types/ArrayType.java
new file mode 100644
index 0000000..5108f32
--- /dev/null
+++ b/vxquery-core/src/main/java/org/apache/vxquery/types/ArrayType.java
@@ -0,0 +1,43 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.vxquery.types;
+
+public final class ArrayType extends AbstractJsonItemType {
+    private static final long serialVersionUID = 1L;
+
+    public static final ArrayType INSTANCE = new ArrayType();
+
+    @Override
+    public int hashCode() {
+        return ArrayType.class.hashCode();
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        return other instanceof ArrayType;
+    }
+
+    @Override
+    public String toString() {
+        return "array";
+    }
+
+    @Override
+    public JsonItemKind getJsonItemKind() {
+        return JsonItemKind.ARRAY;
+    }
+}
diff --git a/vxquery-core/src/main/java/org/apache/vxquery/types/BuiltinTypeQNames.java b/vxquery-core/src/main/java/org/apache/vxquery/types/BuiltinTypeQNames.java
index 9f762ff..ec2163e 100644
--- a/vxquery-core/src/main/java/org/apache/vxquery/types/BuiltinTypeQNames.java
+++ b/vxquery-core/src/main/java/org/apache/vxquery/types/BuiltinTypeQNames.java
@@ -125,4 +125,6 @@
             XQueryConstants.XS_PREFIX);
     public static final QName XSEXT_TYPE_TYPE_QNAME = new QName(XQueryConstants.XSEXT_NSURI, "type",
             XQueryConstants.XSEXT_PREFIX);
+    public static final QName JS_NULL_TYPE_QNAME = new QName(XQueryConstants.JS_NSURI, "null",
+            XQueryConstants.JS_PREFIX);
 }
diff --git a/vxquery-core/src/main/java/org/apache/vxquery/types/BuiltinTypeRegistry.java b/vxquery-core/src/main/java/org/apache/vxquery/types/BuiltinTypeRegistry.java
index 29bb5e2..ab4f627 100644
--- a/vxquery-core/src/main/java/org/apache/vxquery/types/BuiltinTypeRegistry.java
+++ b/vxquery-core/src/main/java/org/apache/vxquery/types/BuiltinTypeRegistry.java
@@ -219,6 +219,7 @@
         types[BuiltinTypeConstants.XS_ANY_URI_TYPE_ID] = XS_ANY_URI;
         types[BuiltinTypeConstants.XS_QNAME_TYPE_ID] = XS_QNAME;
         types[BuiltinTypeConstants.XS_NOTATION_TYPE_ID] = XS_NOTATION;
+        types[BuiltinTypeConstants.JS_NULL_TYPE_ID] = JS_NULL;
 
         typeNames = new QName[BuiltinTypeConstants.BUILTIN_TYPE_COUNT];
         typeNames[BuiltinTypeConstants.XS_ANY_TYPE_ID] = BuiltinTypeQNames.XS_ANY_TYPE_QNAME;
@@ -270,6 +271,7 @@
         typeNames[BuiltinTypeConstants.XS_ANY_URI_TYPE_ID] = BuiltinTypeQNames.XS_ANY_URI_TYPE_QNAME;
         typeNames[BuiltinTypeConstants.XS_QNAME_TYPE_ID] = BuiltinTypeQNames.XS_QNAME_TYPE_QNAME;
         typeNames[BuiltinTypeConstants.XS_NOTATION_TYPE_ID] = BuiltinTypeQNames.XS_NOTATION_TYPE_QNAME;
+        typeNames[BuiltinTypeConstants.JS_NULL_TYPE_ID] = BuiltinTypeQNames.JS_NULL_TYPE_QNAME;
     }
 
     public SchemaType getSchemaTypeById(int id) {
diff --git a/vxquery-core/src/main/java/org/apache/vxquery/types/JsonItemKind.java b/vxquery-core/src/main/java/org/apache/vxquery/types/JsonItemKind.java
new file mode 100644
index 0000000..0af2811
--- /dev/null
+++ b/vxquery-core/src/main/java/org/apache/vxquery/types/JsonItemKind.java
@@ -0,0 +1,23 @@
+/*
+* Licensed to the Apache Software Foundation (ASF) under one or more
+* contributor license agreements.  See the NOTICE file distributed with
+* this work for additional information regarding copyright ownership.
+* The ASF licenses this file to You under the Apache License, Version 2.0
+* (the "License"); you may not use this file except in compliance with
+* the License.  You may obtain a copy of the License at
+*
+*     http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+package org.apache.vxquery.types;
+
+public enum JsonItemKind {
+    ANY,
+    OBJECT,
+    ARRAY
+}
diff --git a/vxquery-core/src/main/java/org/apache/vxquery/types/JsonItemType.java b/vxquery-core/src/main/java/org/apache/vxquery/types/JsonItemType.java
new file mode 100644
index 0000000..f06eebc
--- /dev/null
+++ b/vxquery-core/src/main/java/org/apache/vxquery/types/JsonItemType.java
@@ -0,0 +1,21 @@
+/*
+* Licensed to the Apache Software Foundation (ASF) under one or more
+* contributor license agreements.  See the NOTICE file distributed with
+* this work for additional information regarding copyright ownership.
+* The ASF licenses this file to You under the Apache License, Version 2.0
+* (the "License"); you may not use this file except in compliance with
+* the License.  You may obtain a copy of the License at
+*
+*     http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+package org.apache.vxquery.types;
+
+public interface JsonItemType extends StructuredItemType {
+    public JsonItemKind getJsonItemKind();
+}
diff --git a/vxquery-core/src/main/java/org/apache/vxquery/types/NodeType.java b/vxquery-core/src/main/java/org/apache/vxquery/types/NodeType.java
index cd43f97..ef4ba7d 100644
--- a/vxquery-core/src/main/java/org/apache/vxquery/types/NodeType.java
+++ b/vxquery-core/src/main/java/org/apache/vxquery/types/NodeType.java
@@ -16,6 +16,6 @@
 */
 package org.apache.vxquery.types;
 
-public interface NodeType extends ItemType {
+public interface NodeType extends StructuredItemType {
     public NodeKind getNodeKind();
 }
diff --git a/vxquery-core/src/main/java/org/apache/vxquery/types/ObjectType.java b/vxquery-core/src/main/java/org/apache/vxquery/types/ObjectType.java
new file mode 100644
index 0000000..b61f3b4
--- /dev/null
+++ b/vxquery-core/src/main/java/org/apache/vxquery/types/ObjectType.java
@@ -0,0 +1,43 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.vxquery.types;
+
+public final class ObjectType extends AbstractJsonItemType {
+    private static final long serialVersionUID = 1L;
+
+    public static final ObjectType INSTANCE = new ObjectType();
+
+    @Override
+    public int hashCode() {
+        return ObjectType.class.hashCode();
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        return other instanceof ObjectType;
+    }
+
+    @Override
+    public JsonItemKind getJsonItemKind() {
+        return JsonItemKind.OBJECT;
+    }
+
+    @Override
+    public String toString() {
+        return "object";
+    }
+}
diff --git a/vxquery-core/src/main/java/org/apache/vxquery/types/SequenceType.java b/vxquery-core/src/main/java/org/apache/vxquery/types/SequenceType.java
index 2986a8c..0066967 100644
--- a/vxquery-core/src/main/java/org/apache/vxquery/types/SequenceType.java
+++ b/vxquery-core/src/main/java/org/apache/vxquery/types/SequenceType.java
@@ -30,7 +30,7 @@
     private Quantifier quantifier;
 
     static {
-        Map<ItemType, SequenceType[]> types = new LinkedHashMap<ItemType, SequenceType[]>();
+        Map<ItemType, SequenceType[]> types = new LinkedHashMap<>();
 
         createBuiltinEntry(types, BuiltinTypeRegistry.XS_ANY_ATOMIC);
         createBuiltinEntry(types, BuiltinTypeRegistry.XS_STRING);
@@ -79,6 +79,7 @@
         createBuiltinEntry(types, BuiltinTypeRegistry.XS_ANY_URI);
         createBuiltinEntry(types, BuiltinTypeRegistry.XS_QNAME);
         createBuiltinEntry(types, BuiltinTypeRegistry.XS_NOTATION);
+        createBuiltinEntry(types, BuiltinTypeRegistry.JS_NULL);
 
         createBuiltinEntry(types, AnyItemType.INSTANCE);
         createBuiltinEntry(types, AnyNodeType.INSTANCE);
@@ -88,14 +89,24 @@
         createBuiltinEntry(types, CommentType.INSTANCE);
         createBuiltinEntry(types, ProcessingInstructionType.ANYPI);
 
+        createBuiltinEntry(types, ArrayType.INSTANCE);
+        createBuiltinEntry(types, ObjectType.INSTANCE);
+
         BUILTIN_SEQ_TYPES = Collections.unmodifiableMap(types);
     }
 
+    private SequenceType(ItemType itemType, Quantifier quantifier) {
+        this.itemType = itemType;
+        this.quantifier = quantifier;
+    }
+
     private static void createBuiltinEntry(Map<ItemType, SequenceType[]> types, ItemType itemType) {
-        types.put(itemType, new SequenceType[] { new SequenceType(itemType, Quantifier.QUANT_ZERO),
-                new SequenceType(itemType, Quantifier.QUANT_ONE),
-                new SequenceType(itemType, Quantifier.QUANT_QUESTION),
-                new SequenceType(itemType, Quantifier.QUANT_STAR), new SequenceType(itemType, Quantifier.QUANT_PLUS), });
+        types.put(itemType,
+                new SequenceType[] { new SequenceType(itemType, Quantifier.QUANT_ZERO),
+                        new SequenceType(itemType, Quantifier.QUANT_ONE),
+                        new SequenceType(itemType, Quantifier.QUANT_QUESTION),
+                        new SequenceType(itemType, Quantifier.QUANT_STAR),
+                        new SequenceType(itemType, Quantifier.QUANT_PLUS), });
     }
 
     public static SequenceType create(ItemType itemType, Quantifier quantifier) {
@@ -106,11 +117,6 @@
         return types[quantifier.ordinal()];
     }
 
-    private SequenceType(ItemType itemType, Quantifier quantifier) {
-        this.itemType = itemType;
-        this.quantifier = quantifier;
-    }
-
     public ItemType getItemType() {
         return itemType;
     }
diff --git a/vxquery-core/src/main/java/org/apache/vxquery/types/StructuredItemType.java b/vxquery-core/src/main/java/org/apache/vxquery/types/StructuredItemType.java
new file mode 100644
index 0000000..eb8a0af
--- /dev/null
+++ b/vxquery-core/src/main/java/org/apache/vxquery/types/StructuredItemType.java
@@ -0,0 +1,20 @@
+/*
+* Licensed to the Apache Software Foundation (ASF) under one or more
+* contributor license agreements.  See the NOTICE file distributed with
+* this work for additional information regarding copyright ownership.
+* The ASF licenses this file to You under the Apache License, Version 2.0
+* (the "License"); you may not use this file except in compliance with
+* the License.  You may obtain a copy of the License at
+*
+*     http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+package org.apache.vxquery.types;
+
+public interface StructuredItemType extends ItemType {
+}
diff --git a/vxquery-core/src/main/java/org/apache/vxquery/types/TypeUtils.java b/vxquery-core/src/main/java/org/apache/vxquery/types/TypeUtils.java
index f76a423..6dfa677 100644
--- a/vxquery-core/src/main/java/org/apache/vxquery/types/TypeUtils.java
+++ b/vxquery-core/src/main/java/org/apache/vxquery/types/TypeUtils.java
@@ -26,8 +26,8 @@
         return createSequenceType(RootStaticContextImpl.INSTANCE, str);
     }
 
-    public static SequenceType createSequenceType(StaticContext sCtx, String str) {
-        str = str.trim();
+    public static SequenceType createSequenceType(StaticContext sCtx, String s) {
+        String str = s.trim();
         Quantifier q = Quantifier.QUANT_ONE;
         if (str.endsWith("?")) {
             q = Quantifier.QUANT_QUESTION;
@@ -43,6 +43,12 @@
         ItemType it;
         if (str.equals("item()")) {
             it = AnyItemType.INSTANCE;
+        } else if (str.equals("json-item()")) {
+            it = AnyJsonItemType.INSTANCE;
+        } else if (str.equals("object()")) {
+            it = ObjectType.INSTANCE;
+        } else if (str.equals("array()")) {
+            it = ArrayType.INSTANCE;
         } else if (str.equals("node()")) {
             it = AnyNodeType.INSTANCE;
         } else if (str.equals("document-node()")) {
diff --git a/vxquery-core/src/main/java/org/apache/vxquery/xmlquery/query/XQueryConstants.java b/vxquery-core/src/main/java/org/apache/vxquery/xmlquery/query/XQueryConstants.java
index d8fdf94..29b9bcb 100644
--- a/vxquery-core/src/main/java/org/apache/vxquery/xmlquery/query/XQueryConstants.java
+++ b/vxquery-core/src/main/java/org/apache/vxquery/xmlquery/query/XQueryConstants.java
@@ -36,13 +36,31 @@
     public static final String LOCAL_NSURI = "http://www.w3.org/2005/xquery-local-functions";
 
     public static final String ERR_NSURI = "http://www.w3.org/2005/xqt-errors";
-    
+
     public static final String OP_PREFIX = "op";
     public static final String OP_NSURI = "urn:org.apache.vxquery.operators";
 
     public static final String OPEXT_PREFIX = "opext";
     public static final String OPEXT_NSURI = "urn:org.apache.vxquery.operators-ext";
 
+    public static final String JS_PREFIX = "js";
+    public static final String JS_NSURI = "http://jsoniq.org/types";
+
+    public static final String JN_PREFIX = "jn";
+    public static final String JN_NSURI = "http://jsoniq.org/functions";
+
+    public static final String LIBJN_PREFIX = "libjn";
+    public static final String LIBJN_NSURI = "http://jsoniq.org/function-library";
+
+    public static final String JERR_PREFIX = "jerr";
+    public static final String JERR_NSURI = "http://jsoniq.org/errors";
+
+    public static final String JUPD_PREFIX = "jupd";
+    public static final String JUPD_NSURI = "http://jsoniq.org/updates";
+
+    public static final String JDM_PREFIX = "jdm";
+    public static final String JDM_NSURI = "urn:org.apache.vxquery.jsoniq-data-model";
+
     private XQueryConstants() {
     }
 
@@ -57,7 +75,7 @@
     public enum TypeQuantifier {
         QUANT_QUESTION, QUANT_STAR, QUANT_PLUS
     }
-    
+
     public enum PathType {
         SLASH,
         SLASH_SLASH,