diff --git a/artemis-selector/src/main/java/org/apache/activemq/artemis/selector/filter/UnaryExpression.java b/artemis-selector/src/main/java/org/apache/activemq/artemis/selector/filter/UnaryExpression.java
index 4c106bd050..e70de83861 100755
--- a/artemis-selector/src/main/java/org/apache/activemq/artemis/selector/filter/UnaryExpression.java
+++ b/artemis-selector/src/main/java/org/apache/activemq/artemis/selector/filter/UnaryExpression.java
@@ -61,15 +61,12 @@ public abstract class UnaryExpression implements Expression {
                                                       final boolean not) {
 
       // Use a HashSet if there are many elements.
-      Collection<Object> t;
-      if (elements.size() == 0) {
-         t = null;
-      } else if (elements.size() < 5) {
-         t = elements;
+      final Collection<Object> inList;
+      if (elements.size() < 5) {
+         inList = elements;
       } else {
-         t = new HashSet<>(elements);
+         inList = new HashSet<>(elements);
       }
-      final Collection<Object> inList = t;
 
       return new BooleanUnaryExpression(right) {
          @Override
@@ -83,7 +80,7 @@ public abstract class UnaryExpression implements Expression {
                return null;
             }
 
-            return (inList != null && inList.contains(rvalue)) ^ not;
+            return inList.contains(rvalue) ^ not;
          }
 
          @Override
diff --git a/artemis-selector/src/test/java/org/apache/activemq/artemis/selector/filter/UnaryExpressionTest.java b/artemis-selector/src/test/java/org/apache/activemq/artemis/selector/filter/UnaryExpressionTest.java
index 6e6ab43c64..8f1b1a19bc 100755
--- a/artemis-selector/src/test/java/org/apache/activemq/artemis/selector/filter/UnaryExpressionTest.java
+++ b/artemis-selector/src/test/java/org/apache/activemq/artemis/selector/filter/UnaryExpressionTest.java
@@ -16,6 +16,8 @@
  */
 package org.apache.activemq.artemis.selector.filter;
 
+import java.util.Collections;
+
 import org.apache.activemq.artemis.selector.impl.SelectorParser;
 import org.junit.Assert;
 import org.junit.Test;
@@ -30,4 +32,13 @@ public class UnaryExpressionTest {
       Assert.assertTrue("Created unary expression 2", expr2 instanceof UnaryExpression);
       Assert.assertEquals("Unary expressions are equal", expr1, expr2);
    }
+
+   @Test
+   public void testInExpressionToString() throws Exception {
+      BooleanExpression expr;
+      expr = UnaryExpression.createInExpression(new PropertyExpression("foo"), Collections.<Object>singletonList("bar"), false);
+      Assert.assertTrue(expr.toString().matches("foo\\s+IN\\s+.*bar.*"));
+      expr = UnaryExpression.createInExpression(new PropertyExpression("foo"), Collections.emptyList(), false);
+      Assert.assertTrue(expr.toString().matches("foo\\s+IN\\s+.*"));
+   }
 }