diff --git a/xmp-core/src/main/java/org/verapdf/xmp/containers/StaticXmpCoreContainers.java b/xmp-core/src/main/java/org/verapdf/xmp/containers/StaticXmpCoreContainers.java
index b00767f69..b8a48476e 100644
--- a/xmp-core/src/main/java/org/verapdf/xmp/containers/StaticXmpCoreContainers.java
+++ b/xmp-core/src/main/java/org/verapdf/xmp/containers/StaticXmpCoreContainers.java
@@ -1,6 +1,7 @@
 package org.verapdf.xmp.containers;
 
-import java.util.*;
+import java.util.HashMap;
+import java.util.Map;
 
 public class StaticXmpCoreContainers {
 
@@ -14,23 +15,46 @@ public class StaticXmpCoreContainers {
      */
     private static final ThreadLocal<Map<String, String>> prefixToNamespaceMap = new ThreadLocal<>();
 
+    /**
+     * Clears all namespaces and prefixes.
+     */
     public static void clearAllContainers() {
         namespaceToPrefixMap.set(new HashMap<>());
         prefixToNamespaceMap.set(new HashMap<>());
     }
 
+    /**
+     * Gets namespaces map.
+     *
+     * @return a map of namespaces
+     */
     public static Map<String, String> getNamespaceToPrefixMap() {
         return namespaceToPrefixMap.get();
     }
 
+    /**
+     * Gets prefixes map.
+     *
+     * @return a map of prefixes
+     */
     public static Map<String, String> getPrefixToNamespaceMap() {
         return prefixToNamespaceMap.get();
     }
 
+    /**
+     * Sets namespaces.
+     *
+     * @param namespaceToPrefixMap a map of namespaces
+     */
     public static void setNamespaceToPrefixMap(Map<String, String> namespaceToPrefixMap) {
         StaticXmpCoreContainers.namespaceToPrefixMap.set(namespaceToPrefixMap);
     }
 
+    /**
+     * Sets prefixes.
+     *
+     * @param prefixToNamespaceMap a map of prefixes
+     */
     public static void setPrefixToNamespaceMap(Map<String, String> prefixToNamespaceMap) {
         StaticXmpCoreContainers.prefixToNamespaceMap.set(prefixToNamespaceMap);
     }
diff --git a/xmp-core/src/main/java/org/verapdf/xmp/impl/VeraPDFExtensionSchemaDefinition.java b/xmp-core/src/main/java/org/verapdf/xmp/impl/VeraPDFExtensionSchemaDefinition.java
index de41d1152..b857bce6f 100644
--- a/xmp-core/src/main/java/org/verapdf/xmp/impl/VeraPDFExtensionSchemaDefinition.java
+++ b/xmp-core/src/main/java/org/verapdf/xmp/impl/VeraPDFExtensionSchemaDefinition.java
@@ -1,27 +1,36 @@
 package org.verapdf.xmp.impl;
 
-import org.verapdf.xmp.XMPConst;
-import org.verapdf.xmp.XMPException;
-import org.verapdf.xmp.options.PropertyOptions;
-
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import org.verapdf.xmp.XMPConst;
+import org.verapdf.xmp.XMPException;
+import org.verapdf.xmp.options.PropertyOptions;
 
 public class VeraPDFExtensionSchemaDefinition {
 
     private static final String PROPERTY = "property";
-    public static final String NAMESPACE_URI = "namespaceURI";
+    private static final String NAMESPACE_URI = "namespaceURI";
     private static final String PREFIX = "prefix";
     private static final String SCHEMA = "schema";
     private static final String PDFA_SCHEMA_PREFIX = "pdfaSchema";
 
     private final VeraPDFXMPNode xmpNode;
 
+    /**
+     * VeraPDF extension schema.
+     *
+     * @param xmpNode a metadata node
+     */
     public VeraPDFExtensionSchemaDefinition(VeraPDFXMPNode xmpNode) {
         this.xmpNode = xmpNode;
     }
 
+    /**
+     * Gets schema properties.
+     *
+     * @return schema properties
+     */
     public List<VeraPDFExtensionSchemaProperty> getExtensionSchemaProperties() {
         if (this.xmpNode != null) {
             List<VeraPDFExtensionSchemaProperty> res = new ArrayList<>();
@@ -39,7 +48,12 @@ public List<VeraPDFExtensionSchemaProperty> getExtensionSchemaProperties() {
         }
         return Collections.emptyList();
     }
-    
+
+    /**
+     * Gets property of xmp node.
+     *
+     * @return xmp node property value
+     */
     public VeraPDFXMPNode getPropertiesNode() {
         if (this.xmpNode != null) {
             for (VeraPDFXMPNode child : this.xmpNode.getChildren()) {
@@ -51,12 +65,25 @@ public VeraPDFXMPNode getPropertiesNode() {
         return null;
     }
 
-    public void addExtensionSchemaProperty(VeraPDFExtensionSchemaProperty propertyDefinitionXMPNode) throws XMPException {
+    /**
+     * Adds extension schema property.
+     *
+     * @param propertyDefinitionXMPNode a property of xmp node
+     *
+     * @throws XMPException exceptions from the metadata processing
+     */
+    public void addExtensionSchemaProperty(VeraPDFExtensionSchemaProperty propertyDefinitionXMPNode)
+            throws XMPException {
         if (this.xmpNode != null) {
             getPropertiesNode().getOriginalNode().addChild(propertyDefinitionXMPNode.getXmpNode());
         }
     }
 
+    /**
+     * Get namespaces URI of xmp node.
+     *
+     * @return xmp node namespace value
+     */
     public String getNamespaceURI() {
         for (VeraPDFXMPNode child : this.xmpNode.getChildren()) {
             if (XMPConst.NS_PDFA_SCHEMA.equals(child.getNamespaceURI()) && NAMESPACE_URI.equals(child.getName())) {
@@ -66,6 +93,11 @@ public String getNamespaceURI() {
         return null;
     }
 
+    /**
+     * Get prefix of xmp node.
+     *
+     * @return xmp node prefix value
+     */
     public String getPrefix() {
         for (VeraPDFXMPNode child : this.xmpNode.getChildren()) {
             if (XMPConst.NS_PDFA_SCHEMA.equals(child.getNamespaceURI()) && PREFIX.equals(child.getName())) {
@@ -75,19 +107,36 @@ public String getPrefix() {
         return null;
     }
 
+    /**
+     * Gets xmp node.
+     *
+     * @return original xmp node from metadata
+     */
     public XMPNode getXmpNode() {
         return xmpNode.getOriginalNode();
     }
 
-    public static VeraPDFExtensionSchemaDefinition createExtensionSchemaDefinitionNode(String schema, String namespaceURI, String prefix) throws XMPException {
-        XMPNode node = new XMPNode(XMPConst.ARRAY_ITEM_NAME,"", new PropertyOptions(PropertyOptions.STRUCT), "rdf");
+    /**
+     * Creates schema definition node.
+     *
+     * @param schema       a xmp schema definition
+     * @param namespaceURI a namespace URI of the node
+     * @param prefix       a prefix of the node
+     *
+     * @return xmp extension schema
+     *
+     * @throws XMPException exceptions from the metadata processing
+     */
+    public static VeraPDFExtensionSchemaDefinition createExtensionSchemaDefinitionNode(String schema,
+            String namespaceURI, String prefix) throws XMPException {
+        XMPNode node = new XMPNode(XMPConst.ARRAY_ITEM_NAME, "", new PropertyOptions(PropertyOptions.STRUCT), "rdf");
         node.addChild(new XMPNode(PDFA_SCHEMA_PREFIX + ":" + SCHEMA, schema,
                 new PropertyOptions(PropertyOptions.NO_OPTIONS), PDFA_SCHEMA_PREFIX));
         node.addChild(new XMPNode(PDFA_SCHEMA_PREFIX + ":" + NAMESPACE_URI, namespaceURI,
                 new PropertyOptions(PropertyOptions.NO_OPTIONS), PDFA_SCHEMA_PREFIX));
         node.addChild(new XMPNode(PDFA_SCHEMA_PREFIX + ":" + PREFIX, prefix,
                 new PropertyOptions(PropertyOptions.NO_OPTIONS), PDFA_SCHEMA_PREFIX));
-        node.addChild(new XMPNode(PDFA_SCHEMA_PREFIX + ":" + PROPERTY,"",
+        node.addChild(new XMPNode(PDFA_SCHEMA_PREFIX + ":" + PROPERTY, "",
                 new PropertyOptions(PropertyOptions.ARRAY + PropertyOptions.ARRAY_ORDERED), PDFA_SCHEMA_PREFIX));
         return new VeraPDFExtensionSchemaDefinition(VeraPDFXMPNode.fromXMPNode(node));
     }