diff --git a/src/main/groovy/com/athaydes/spockframework/report/internal/HtmlReportCreator.groovy b/src/main/groovy/com/athaydes/spockframework/report/internal/HtmlReportCreator.groovy
index b369cbe..18b8315 100644
--- a/src/main/groovy/com/athaydes/spockframework/report/internal/HtmlReportCreator.groovy
+++ b/src/main/groovy/com/athaydes/spockframework/report/internal/HtmlReportCreator.groovy
@@ -279,10 +279,9 @@ class HtmlReportCreator extends AbstractHtmlCreator<SpecData>
 
                 List<IterationInfo> iterations = run
                         ? run.copyFailuresByIteration().keySet()
-                        .toList().findAll { it.iterationIndex >= 0 }
-                        .sort { it.iterationIndex }
-                        : List.of()
-                def extraInfo = List.of()
+                        .toList().sort { it.iterationIndex }
+                        : Collections.emptyList()
+                def extraInfo = Collections.emptyList()
                 def multipleIterations = iterations.size() > 1
                 if ( run && multipleIterations ) {
                     extraInfo = iterations.collectMany {
diff --git a/src/test/groovy/com/athaydes/spockframework/report/engine/CanRunSpockSpecs.groovy b/src/test/groovy/com/athaydes/spockframework/report/engine/CanRunSpockSpecs.groovy
index cbaf4c7..a80bb6b 100644
--- a/src/test/groovy/com/athaydes/spockframework/report/engine/CanRunSpockSpecs.groovy
+++ b/src/test/groovy/com/athaydes/spockframework/report/engine/CanRunSpockSpecs.groovy
@@ -17,14 +17,14 @@ trait CanRunSpockSpecs {
         else execute( selectClass( specClass ) )
     }
 
-    private static void execute( DiscoverySelector selector, Consumer<EventStatistics> statisticsConsumer ) {
+    private void execute( DiscoverySelector selector, Consumer<EventStatistics> statisticsConsumer ) {
         execute( selector )
                 .testEvents()
                 .debug()
                 .assertStatistics( statisticsConsumer )
     }
 
-    private static EngineExecutionResults execute( DiscoverySelector selector ) {
+    private EngineExecutionResults execute( DiscoverySelector selector ) {
         return EngineTestKit
                 .engine( "spock" )
                 .selectors( selector )