diff --git a/jena-arq/src/main/java/org/apache/jena/sparql/core/DatasetGraphCopyAdd.java b/jena-arq/src/main/java/org/apache/jena/sparql/core/DatasetGraphCopyAdd.java
deleted file mode 100644
index 296b555fb91..00000000000
--- a/jena-arq/src/main/java/org/apache/jena/sparql/core/DatasetGraphCopyAdd.java
+++ /dev/null
@@ -1,41 +0,0 @@
-/**
- * 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.jena.sparql.core;
-
-import org.apache.jena.graph.Graph ;
-import org.apache.jena.graph.Node ;
-
-/** Override {@link DatasetGraph#addGraph} so that it always copies
- * content from the added graph data.
- */
-
-/*package*/ class DatasetGraphCopyAdd extends DatasetGraphWrapper 
-{
-    public DatasetGraphCopyAdd(boolean x , DatasetGraph dsg) {
-        super(dsg);
-    }
-    
-    @Override
-    public void addGraph(Node graphName, Graph graph) {
-        graph.find(null,null,null).forEachRemaining(t-> {
-            Quad q = Quad.create(graphName, t) ;
-            super.add(q) ;
-        }) ;
-    }
-}
\ No newline at end of file
diff --git a/jena-arq/src/main/java/org/apache/jena/sparql/expr/ExprSystem.java b/jena-arq/src/main/java/org/apache/jena/sparql/expr/ExprSystem.java
index dc312921808..62cd25e3858 100644
--- a/jena-arq/src/main/java/org/apache/jena/sparql/expr/ExprSystem.java
+++ b/jena-arq/src/main/java/org/apache/jena/sparql/expr/ExprSystem.java
@@ -25,7 +25,7 @@
 
 public abstract class ExprSystem extends ExprFunction0
 {
-    private final Symbol systemSymbol ;
+    protected final Symbol systemSymbol ;
 
     protected ExprSystem(String fName, Symbol systemSymbol)
     {
@@ -41,12 +41,11 @@ public NodeValue eval(FunctionEnv env)
         if ( obj == null )
             throw new ExprEvalException("null for system symbol: "+systemSymbol) ;
         if ( ! ( obj instanceof Node ) )
-            throw new ExprEvalException("Not a Node: "+Lib.className(obj)) ;
+            throw new ExprEvalException("ExprSystem: Not a Node: "+Lib.className(obj)) ;
         
         Node n = (Node)obj ;
-//        if ( n == null )
-//            throw new ExprEvalException("No value for system variable: "+systemSymbol) ;  
-        // NodeValue.makeNode could have a cache.
+        if ( n == null )
+            throw new ExprEvalException("No value for system variable: "+systemSymbol) ;  
         NodeValue nv = NodeValue.makeNode(n) ;
         return nv ;
     }
diff --git a/jena-arq/src/main/java/org/apache/jena/sparql/sse/builders/BuilderLib.java b/jena-arq/src/main/java/org/apache/jena/sparql/sse/builders/BuilderLib.java
index a154ac27761..ed7b3e8dbd8 100644
--- a/jena-arq/src/main/java/org/apache/jena/sparql/sse/builders/BuilderLib.java
+++ b/jena-arq/src/main/java/org/apache/jena/sparql/sse/builders/BuilderLib.java
@@ -18,168 +18,135 @@
 
 package org.apache.jena.sparql.sse.builders;
 
-import org.apache.jena.sparql.sse.Item ;
-import org.apache.jena.sparql.sse.ItemList ;
-import org.apache.jena.sparql.sse.ItemLocation ;
-
-public class BuilderLib
-{
- 
-    public static void checkNode(Item item)
-    {
-        if ( item.isNode() ) 
-            return ;
-        broken(item, "Not a node: "+item.shortString()) ;
-    }
-    
-    public static void checkSymbol(Item item)
-    {
-        if ( item.isSymbol() ) 
-            return ;
-        broken(item, "Not a symbol: "+item.shortString()) ;
-    }
-    
-    public static void checkTagged(Item item, String tag, String msg)
-    {
-        if ( item.isTagged(tag) ) return ;
-        broken(item, msg, item) ;
-    }
-
-    public static void checkTagged(Item item, int len, String tag, String msg)
-    {
-        if ( item.isTagged(tag) && item.getList().size() == len ) 
-            return ;
-        broken(item, msg, item) ;
-    }
-
-    
-    public static void checkTag(ItemList list, String tag)
-    {
+import org.apache.jena.sparql.sse.Item;
+import org.apache.jena.sparql.sse.ItemList;
+import org.apache.jena.sparql.sse.ItemLocation;
+
+public class BuilderLib {
+
+    public static void checkNode(Item item) {
+        if ( item.isNode() )
+            return;
+        broken(item, "Not a node: " + item.shortString());
+    }
+
+    public static void checkSymbol(Item item) {
+        if ( item.isSymbol() )
+            return;
+        broken(item, "Not a symbol: " + item.shortString());
+    }
+
+    public static void checkTagged(Item item, String tag, String msg) {
+        if ( item.isTagged(tag) )
+            return;
+        broken(item, msg, item);
+    }
+
+    public static void checkTagged(Item item, int len, String tag, String msg) {
+        if ( item.isTagged(tag) && item.getList().size() == len )
+            return;
+        broken(item, msg, item);
+    }
+
+    public static void checkTag(ItemList list, String tag) {
         if ( list.size() == 0 )
-            broken(list, "Empty list") ;
-        if ( ! list.get(0).isSymbolIgnoreCase(tag) )
-            broken(list, "List does not start ("+tag+ "...) : "+list.shortString()) ;
+            broken(list, "Empty list");
+        if ( !list.get(0).isSymbolIgnoreCase(tag) )
+            broken(list, "List does not start (" + tag + "...) : " + list.shortString());
     }
 
-    public static void checkList(Item item)
-    {
-        if ( item.isList() ) 
-            return ;
-        broken(item, "Not a list: "+item.shortString()) ;
+    public static void checkList(Item item) {
+        if ( item.isList() )
+            return;
+        broken(item, "Not a list: " + item.shortString());
     }
 
-    public static void checkList(Item item, String msg)
-    {
+    public static void checkList(Item item, String msg) {
         if ( item.isList() )
-            return ;
-        if ( msg == null && item.isSymbol())
-            msg = "Attempt to use a symbol where list expected: "+item.shortString() ;
-        if ( msg == null && item.isNode())
-            msg = "Attempt to use a node where list expected: "+item.shortString() ;
+            return;
+        if ( msg == null && item.isSymbol() )
+            msg = "Attempt to use a symbol where list expected: " + item.shortString();
+        if ( msg == null && item.isNode() )
+            msg = "Attempt to use a node where list expected: " + item.shortString();
         if ( msg == null )
-            msg = "Not a list" ;
-        broken(item, msg) ; 
-    }
-    
-    public static void warning(ItemLocation location, String msg)
-    {
-        msg = msg(location, msg) ;
-        System.err.println(msg) ;
+            msg = "Not a list";
+        broken(item, msg);
     }
 
-    public static void checkLength(int len1, int len2, ItemList list, String msg)
-    {
+    public static void checkLength(int len1, int len2, ItemList list, String msg) {
         if ( list.size() >= len1 && list.size() <= len2 )
-            return ; 
+            return;
         if ( msg == null )
-            msg =  "Wrong number of arguments: ("+len1+"-"+len2+")/"+list.size()+" : "+list.shortString() ;
+            msg = "Wrong number of arguments: (" + len1 + "-" + len2 + ")/" + list.size() + " : " + list.shortString();
         else
-            msg = msg+" : "+list.shortString() ;
-        broken(list, msg) ;
-    }
-    
-    
-    
-    public static void checkLength(int len, ItemList list, String msg)
-    {
+            msg = msg + " : " + list.shortString();
+        broken(list, msg);
+    }
+
+    public static void checkLength(int len, ItemList list, String msg) {
         if ( list.size() == len )
-            return ;
-        
+            return;
+
         if ( msg == null )
-            msg =  "Wrong number of arguments: "+len+"/"+list.size()+" : "+list.shortString() ;
+            msg = "Wrong number of arguments: " + len + "/" + list.size() + " : " + list.shortString();
         else
-            msg = msg+" : "+list.shortString() ;
-        broken(list, msg) ;
+            msg = msg + " : " + list.shortString();
+        broken(list, msg);
     }
 
-    public static void checkLengthAtLeast(int len, ItemList list, String msg)
-    {
-        if ( list.size()>= len )
-            return ;
-        
+    public static void checkLengthAtLeast(int len, ItemList list, String msg) {
+        if ( list.size() >= len )
+            return;
+
         if ( msg == null )
-            msg =  "Too few arguments: want > "+len+" :got : "+list.size()+" : "+list.shortString() ;
+            msg = "Too few arguments: want > " + len + " :got : " + list.size() + " : " + list.shortString();
         else
-            msg = msg+" : "+list.shortString() ;
-        broken(list, msg) ;
-    }
-    
-    public static void broken(Item item, String msg)
-    {
-        broken(item, msg, item) ;
-    }
-    
-    public static void broken(String msg)
-    {
-        System.err.println(msg) ;
-        exception(msg) ;
-    }
-    
-    public static void exception(String msg)
-    {
-        throw new ExprBuildException(msg) ;
-    }
-    
-    public static void broken(ItemLocation location, String msg, Item item)
-    {
-        msg = msg(location, msg) ;
-        System.err.println(msg+": "+item.shortString()) ;
-        exception(msg) ;
-    }
-
-    public static void broken(ItemList list, String msg)
-    {
-        broken(list, msg, list) ; 
-    }
-
-    public static void broken(ItemLocation location, String msg, ItemList list)
-    {
-        msg = msg(location, msg) ;
-        System.err.println(msg+": "+list.shortString()) ;
-        exception(msg) ;
-    }
-    
-    public static void broken(ItemLocation location, String msg)
-    {
-        msg = msg(location, msg) ;
-        System.err.println(msg) ;
-        exception(msg) ;
-    }
-    
-    public static String msg(ItemLocation location, String msg)
-    {
+            msg = msg + " : " + list.shortString();
+        broken(list, msg);
+    }
+
+    public static void broken(Item item, String msg) {
+        broken(item, msg, item);
+    }
+
+    public static void broken(String msg) {
+        exception(msg);
+    }
+
+    public static void exception(String msg) {
+        throw new ExprBuildException(msg);
+    }
+
+    public static void broken(ItemLocation location, String msg, Item item) {
+        msg = msg(location, msg);
+        exception(msg);
+    }
+
+    public static void broken(ItemList list, String msg) {
+        broken(list, msg, list);
+    }
+
+    public static void broken(ItemLocation location, String msg, ItemList list) {
+        msg = msg(location, msg);
+        exception(msg);
+    }
+
+    public static void broken(ItemLocation location, String msg) {
+        msg = msg(location, msg);
+        exception(msg);
+    }
+
+    public static String msg(ItemLocation location, String msg) {
         if ( location != null )
-            msg = location.location()+": "+msg ;
-        return msg ;
+            msg = location.location() + ": " + msg;
+        return msg;
     }
 
-    public static ItemList skipTag(ItemList list, String tag)
-    {
-        if ( list.size() > 0 )
-        {
+    public static ItemList skipTag(ItemList list, String tag) {
+        if ( list.size() > 0 ) {
             if ( list.get(0).isSymbol(tag) )
-                list = list.cdr() ;
+                list = list.cdr();
         }
-        return list ;
+        return list;
     }
 }
diff --git a/jena-arq/src/main/java/org/apache/jena/sparql/util/FmtUtils.java b/jena-arq/src/main/java/org/apache/jena/sparql/util/FmtUtils.java
index 8452fbeeab4..e9a3adaa9c2 100644
--- a/jena-arq/src/main/java/org/apache/jena/sparql/util/FmtUtils.java
+++ b/jena-arq/src/main/java/org/apache/jena/sparql/util/FmtUtils.java
@@ -49,7 +49,7 @@ public class FmtUtils
 {
     // OLD CODE - being replaced by riot.NodeFmtLib
     
-    // Consider withdrawing non-serialzation context forms of this.
+    // Consider withdrawing non-serialization context forms of this.
     // Or a temporary SerialzationContext does not abbreviate bNodes.
     static final String indentPrefix = "  " ;
     public static boolean multiLineExpr = false ;