test for immutable collection before attempting to remove CREATE_NEW …

…option. (#264)

src/main/java/software/amazon/nio/spi/s3/S3WritableByteChannel.java

@@ -1,5 +1,6 @@
 package software.amazon.nio.spi.s3;
 
+import org.slf4j.Logger;
 import software.amazon.awssdk.services.s3.S3AsyncClient;
 import software.amazon.awssdk.services.s3.model.GetObjectRequest;
 import software.amazon.awssdk.services.s3.model.PutObjectRequest;
@@ -13,7 +14,12 @@
 import java.nio.ByteBuffer;
 import java.nio.channels.SeekableByteChannel;
 import java.nio.channels.WritableByteChannel;
-import java.nio.file.*;
+import java.nio.file.FileAlreadyExistsException;
+import java.nio.file.Files;
+import java.nio.file.NoSuchFileException;
+import java.nio.file.OpenOption;
+import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
 import java.util.Objects;
 import java.util.Set;
 import java.util.concurrent.CompletableFuture;
@@ -31,6 +37,8 @@ class S3WritableByteChannel implements WritableByteChannel {
 
     private boolean open;
 
+    Logger logger = org.slf4j.LoggerFactory.getLogger(S3WritableByteChannel.class);
+
     S3WritableByteChannel(S3Path path, S3AsyncClient client, Set<? extends OpenOption> options, Long timeout, TimeUnit timeUnit) throws IOException {
         Objects.requireNonNull(path);
         Objects.requireNonNull(client);
@@ -69,7 +77,16 @@ class S3WritableByteChannel implements WritableByteChannel {
                 }
             }
 
-            options.remove(StandardOpenOption.CREATE_NEW);
+            try {
+                options.remove(StandardOpenOption.CREATE_NEW);
+            } catch (UnsupportedOperationException e) {
+                if (options.isEmpty() || !options.contains(StandardOpenOption.CREATE_NEW)) {
+                    // options is immutable but it doesn't matter because the value isn't there anyway.
+                    logger.debug("Could not remove CREATE_NEW option as the operation is unsupported on options", e);
+                } else {
+                    throw e;
+                }
+            }
             channel = Files.newByteChannel(this.tempFile, options);
         } catch (InterruptedException e) {
             Thread.currentThread().interrupt();