fixes #292

Author: wumpz

src/main/java/net/sf/jsqlparser/util/deparser/DeleteDeParser.java

@@ -22,6 +22,7 @@
 package net.sf.jsqlparser.util.deparser;
 
 import net.sf.jsqlparser.expression.ExpressionVisitor;
+import net.sf.jsqlparser.expression.ExpressionVisitorAdapter;
 import net.sf.jsqlparser.statement.delete.Delete;
 
 /**
@@ -30,9 +31,12 @@
  */
 public class DeleteDeParser {
 
-	private StringBuilder buffer;
-    private ExpressionVisitor expressionVisitor;
+	private StringBuilder buffer = new StringBuilder();
+    private ExpressionVisitor expressionVisitor = new ExpressionVisitorAdapter();
 
+    public DeleteDeParser() {
+    }
+    
 	/**
 	 * @param expressionVisitor a {@link ExpressionVisitor} to de-parse
 	 * expressions. It has to share the same<br>

src/main/java/net/sf/jsqlparser/util/deparser/UpdateDeParser.java

@@ -35,6 +35,7 @@
 import net.sf.jsqlparser.statement.select.OrderByVisitor;
 import net.sf.jsqlparser.statement.select.OrderByElement;
 import net.sf.jsqlparser.statement.select.SelectExpressionItem;
+import net.sf.jsqlparser.statement.select.SelectVisitorAdapter;
 /**
  * A class to de-parse (that is, tranform from JSqlParser hierarchy into a
  * string) an {@link net.sf.jsqlparser.statement.update.Update}
@@ -43,7 +44,10 @@ public class UpdateDeParser implements OrderByVisitor {
 
     private StringBuilder buffer = new StringBuilder();
     private ExpressionVisitor expressionVisitor = new ExpressionVisitorAdapter();
-    private SelectVisitor selectVisitor;
+    private SelectVisitor selectVisitor = new SelectVisitorAdapter();
+
+    public UpdateDeParser() {
+    }
 
     /**
      * @param expressionVisitor a {@link ExpressionVisitor} to de-parse