Just initialize in constructor to avoid NPE

Author: dpolivaevUnite

freeplane_plugin_codeexplorer/src/main/java/org/freeplane/plugin/codeexplorer/map/CodeMapPersistenceManager.java

@@ -59,8 +59,7 @@ public void restoreUserContent(CodeMap map) {
             .entrySet().stream()
             .forEach(content -> addToMap(map, content.getKey(), content.getValue()));
             final String attributeViewType = configuration.getAttributeConfiguration().getAttributeViewType();
-            if(attributeViewType != null)
-                AttributeRegistry.getRegistry(map).setAttributeViewType(attributeViewType);
+            AttributeRegistry.getRegistry(map).setAttributeViewType(attributeViewType);
 
         } else {
             AttributeRegistry.getRegistry(map).setAttributeViewType(AttributeTableLayoutModel.HIDE_ALL);

freeplane_plugin_codeexplorer/src/main/java/org/freeplane/plugin/codeexplorer/task/CodeAttributeConfiguration.java

@@ -13,6 +13,11 @@ public class CodeAttributeConfiguration {
     @SerializedName("attributeViewType")
     private  String attributeViewType;
 
+    public CodeAttributeConfiguration() {
+        super();
+        this.attributeViewType = AttributeTableLayoutModel.HIDE_ALL;
+    }
+
     void initialize() {
         if(attributeViewType == null)
             attributeViewType = AttributeTableLayoutModel.HIDE_ALL;