Fix intermittent ConcurrentModificationException thrown from codegen (#5812)

Author: zoewangg

Diff for: codegen/src/main/java/software/amazon/awssdk/codegen/CodeGenerator.java

@@ -26,9 +26,10 @@
 import software.amazon.awssdk.codegen.internal.Jackson;
 import software.amazon.awssdk.codegen.internal.Utils;
 import software.amazon.awssdk.codegen.model.intermediate.IntermediateModel;
+import software.amazon.awssdk.utils.Logger;
 
 public class CodeGenerator {
-
+    private static final Logger log = Logger.loggerFor(CodeGenerator.class);
     private static final String MODEL_DIR_NAME = "models";
 
     private final C2jModels models;
@@ -85,6 +86,7 @@ public void execute() {
             emitCode(intermediateModel);
 
         } catch (Exception e) {
+            log.error(() -> "Failed to generate code. ", e);
             throw new RuntimeException(
                     "Failed to generate code. Exception message : " + e.getMessage(), e);
 

Diff for: codegen/src/main/java/software/amazon/awssdk/codegen/poet/client/traits/HttpChecksumTrait.java

@@ -22,6 +22,7 @@
 import java.util.Locale;
 import java.util.Map;
 import java.util.function.Predicate;
+import java.util.stream.Collectors;
 import software.amazon.awssdk.checksums.DefaultChecksumAlgorithm;
 import software.amazon.awssdk.codegen.model.intermediate.IntermediateModel;
 import software.amazon.awssdk.codegen.model.intermediate.MemberModel;
@@ -141,11 +142,12 @@ private static void configureRequestChecksumCalculation(OperationModel operation
      * with the fastest-to-calculate algorithms first.
      */
     private static void addResponseAlgorithmsCodeBlock(List<String> responseAlgorithms, CodeBlock.Builder codeBuilder) {
-        responseAlgorithms.sort(Comparator.comparingInt(o -> CHECKSUM_ALGORITHM_PRIORITY.getOrDefault(
-            o.toUpperCase(Locale.US), Integer.MAX_VALUE)));
+        List<String> sortedResponseAlgorithms =
+            responseAlgorithms.stream().sorted(Comparator.comparingInt(o -> CHECKSUM_ALGORITHM_PRIORITY.getOrDefault(
+            o.toUpperCase(Locale.US), Integer.MAX_VALUE))).collect(Collectors.toList());
 
         codeBuilder.add(CodeBlock.of(".responseAlgorithmsV2("));
-        List<CodeBlock> responseAlgorithmsCodeBlocks = responseAlgorithmsCodeBlocks(responseAlgorithms);
+        List<CodeBlock> responseAlgorithmsCodeBlocks = responseAlgorithmsCodeBlocks(sortedResponseAlgorithms);
         for (int i = 0; i < responseAlgorithmsCodeBlocks.size(); i++) {
             CodeBlock code = responseAlgorithmsCodeBlocks.get(i);
             codeBuilder.add(code);