diff --git a/src/main/java/org/broadinstitute/hellbender/tools/walkers/haplotypecaller/RampedHaplotypeCallerEngine.java b/src/main/java/org/broadinstitute/hellbender/tools/walkers/haplotypecaller/RampedHaplotypeCallerEngine.java
index f05953978bd..e47245c9f91 100644
--- a/src/main/java/org/broadinstitute/hellbender/tools/walkers/haplotypecaller/RampedHaplotypeCallerEngine.java
+++ b/src/main/java/org/broadinstitute/hellbender/tools/walkers/haplotypecaller/RampedHaplotypeCallerEngine.java
@@ -342,7 +342,7 @@ private void assemble(final CallRegionContext context) {
 
             if (assemblyDebugOutStream != null) {
                 assemblyDebugOutStream.write("\nThere were " + untrimmedAssemblyResult.getHaplotypeList().size() + " haplotypes found. Here they are:");
-                for (final String haplotype : untrimmedAssemblyResult.getHaplotypeList().stream().map(Haplotype::toString).sorted().toList()) {
+                for (final String haplotype : untrimmedAssemblyResult.getHaplotypeList().stream().map(Haplotype::toString).sorted().collect(Collectors.toList())) {
                     assemblyDebugOutStream.write(haplotype);
                 }
             }