diff --git a/example/config.yml b/example/config.yml
index 4459848..dbeff17 100644
--- a/example/config.yml
+++ b/example/config.yml
@@ -19,6 +19,7 @@ out:
   type: s3_parquet
   bucket: example
   region: us-east-1
+  endpoint: http://127.0.0.1:4572
   path_prefix: path/to/my-obj.
   file_ext: snappy.parquet
   compression_codec: snappy
diff --git a/example/with_catalog.yml b/example/with_catalog.yml
index acc4a72..39b4ca0 100644
--- a/example/with_catalog.yml
+++ b/example/with_catalog.yml
@@ -19,6 +19,7 @@ out:
   type: s3_parquet
   bucket: example
   region: us-east-1
+  endpoint: http://127.0.0.1:4572
   path_prefix: path/to/my-obj-2.
   file_ext: snappy.parquet
   compression_codec: snappy
diff --git a/example/with_logicaltypes.yml b/example/with_logicaltypes.yml
index 816aae3..5970cc6 100644
--- a/example/with_logicaltypes.yml
+++ b/example/with_logicaltypes.yml
@@ -19,6 +19,7 @@ out:
   type: s3_parquet
   bucket: example
   region: us-east-1
+  endpoint: http://127.0.0.1:4572
   path_prefix: path/to/my-obj-2.
   file_ext: snappy.parquet
   compression_codec: snappy
diff --git a/src/main/scala/org/embulk/output/s3_parquet/ContextClassLoaderSwapper.scala b/src/main/scala/org/embulk/output/s3_parquet/ContextClassLoaderSwapper.scala
new file mode 100644
index 0000000..cadd27c
--- /dev/null
+++ b/src/main/scala/org/embulk/output/s3_parquet/ContextClassLoaderSwapper.scala
@@ -0,0 +1,18 @@
+package org.embulk.output.s3_parquet
+
+// WARNING: This object should be used for limited purposes only.
+object ContextClassLoaderSwapper {
+
+  def using[A](klass: Class[_])(f: => A): A = {
+    val currentTread = Thread.currentThread()
+    val original = currentTread.getContextClassLoader
+    val target = klass.getClassLoader
+    currentTread.setContextClassLoader(target)
+    try f
+    finally currentTread.setContextClassLoader(original)
+  }
+
+  def usingPluginClass[A](f: => A): A = {
+    using(classOf[S3ParquetOutputPlugin])(f)
+  }
+}
diff --git a/src/main/scala/org/embulk/output/s3_parquet/S3ParquetOutputPlugin.scala b/src/main/scala/org/embulk/output/s3_parquet/S3ParquetOutputPlugin.scala
index 66b8705..cfa109c 100644
--- a/src/main/scala/org/embulk/output/s3_parquet/S3ParquetOutputPlugin.scala
+++ b/src/main/scala/org/embulk/output/s3_parquet/S3ParquetOutputPlugin.scala
@@ -133,15 +133,6 @@ class S3ParquetOutputPlugin extends OutputPlugin {
 
   val logger: Logger = LoggerFactory.getLogger(classOf[S3ParquetOutputPlugin])
 
-  private def withPluginContextClassLoader[A](f: => A): A = {
-    val original: ClassLoader = Thread.currentThread.getContextClassLoader
-    Thread.currentThread.setContextClassLoader(
-      classOf[S3ParquetOutputPlugin].getClassLoader
-    )
-    try f
-    finally Thread.currentThread.setContextClassLoader(original)
-  }
-
   override def transaction(
       config: ConfigSource,
       schema: Schema,
@@ -150,10 +141,9 @@ class S3ParquetOutputPlugin extends OutputPlugin {
   ): ConfigDiff = {
     val task: PluginTask = config.loadConfig(classOf[PluginTask])
 
-    withPluginContextClassLoader {
-      configure(task, schema)
-      control.run(task.dump)
-    }
+    configure(task, schema)
+    control.run(task.dump)
+
     task.getCatalog.ifPresent { catalog =>
       val location =
         s"s3://${task.getBucket}/${task.getPathPrefix.replaceFirst("(.*/)[^/]+$", "$1")}"
@@ -303,34 +293,43 @@ class S3ParquetOutputPlugin extends OutputPlugin {
       task.getTypeOptions,
       task.getColumnOptions
     )
-    val parquetWriter: ParquetWriter[PageReader] = ParquetFileWriter
-      .builder()
-      .withPath(bufferFile)
-      .withSchema(schema)
-      .withLogicalTypeHandlers(logicalTypeHandlers)
-      .withTimestampFormatters(timestampFormatters)
-      .withCompressionCodec(task.getCompressionCodec)
-      .withDictionaryEncoding(
-        task.getEnableDictionaryEncoding.orElse(
-          ParquetProperties.DEFAULT_IS_DICTIONARY_ENABLED
-        )
-      )
-      .withDictionaryPageSize(
-        task.getPageSize.orElse(ParquetProperties.DEFAULT_DICTIONARY_PAGE_SIZE)
-      )
-      .withMaxPaddingSize(
-        task.getMaxPaddingSize.orElse(ParquetWriter.MAX_PADDING_SIZE_DEFAULT)
-      )
-      .withPageSize(
-        task.getPageSize.orElse(ParquetProperties.DEFAULT_PAGE_SIZE)
-      )
-      .withRowGroupSize(
-        task.getBlockSize.orElse(ParquetWriter.DEFAULT_BLOCK_SIZE)
-      )
-      .withValidation(ParquetWriter.DEFAULT_IS_VALIDATING_ENABLED)
-      .withWriteMode(org.apache.parquet.hadoop.ParquetFileWriter.Mode.CREATE)
-      .withWriterVersion(ParquetProperties.DEFAULT_WRITER_VERSION)
-      .build()
+    val parquetWriter: ParquetWriter[PageReader] =
+      ContextClassLoaderSwapper.usingPluginClass {
+        ParquetFileWriter
+          .builder()
+          .withPath(bufferFile)
+          .withSchema(schema)
+          .withLogicalTypeHandlers(logicalTypeHandlers)
+          .withTimestampFormatters(timestampFormatters)
+          .withCompressionCodec(task.getCompressionCodec)
+          .withDictionaryEncoding(
+            task.getEnableDictionaryEncoding.orElse(
+              ParquetProperties.DEFAULT_IS_DICTIONARY_ENABLED
+            )
+          )
+          .withDictionaryPageSize(
+            task.getPageSize.orElse(
+              ParquetProperties.DEFAULT_DICTIONARY_PAGE_SIZE
+            )
+          )
+          .withMaxPaddingSize(
+            task.getMaxPaddingSize.orElse(
+              ParquetWriter.MAX_PADDING_SIZE_DEFAULT
+            )
+          )
+          .withPageSize(
+            task.getPageSize.orElse(ParquetProperties.DEFAULT_PAGE_SIZE)
+          )
+          .withRowGroupSize(
+            task.getBlockSize.orElse(ParquetWriter.DEFAULT_BLOCK_SIZE)
+          )
+          .withValidation(ParquetWriter.DEFAULT_IS_VALIDATING_ENABLED)
+          .withWriteMode(
+            org.apache.parquet.hadoop.ParquetFileWriter.Mode.CREATE
+          )
+          .withWriterVersion(ParquetProperties.DEFAULT_WRITER_VERSION)
+          .build()
+      }
 
     logger.info(
       s"Local Buffer File: $bufferFile, Destination: s3://$destS3bucket/$destS3Key"
diff --git a/src/main/scala/org/embulk/output/s3_parquet/S3ParquetPageOutput.scala b/src/main/scala/org/embulk/output/s3_parquet/S3ParquetPageOutput.scala
index 757ab43..eb0cc22 100644
--- a/src/main/scala/org/embulk/output/s3_parquet/S3ParquetPageOutput.scala
+++ b/src/main/scala/org/embulk/output/s3_parquet/S3ParquetPageOutput.scala
@@ -33,7 +33,9 @@ case class S3ParquetPageOutput(
   override def close(): Unit = {
     synchronized {
       if (!isClosed) {
-        writer.close()
+        ContextClassLoaderSwapper.usingPluginClass {
+          writer.close()
+        }
         isClosed = true
       }
     }
@@ -46,11 +48,12 @@ case class S3ParquetPageOutput(
 
   override def commit(): TaskReport = {
     close()
-    val result: UploadResult = aws.withTransferManager {
-      xfer: TransferManager =>
+    val result: UploadResult = ContextClassLoaderSwapper.usingPluginClass {
+      aws.withTransferManager { xfer: TransferManager =>
         val upload: Upload =
           xfer.upload(destBucket, destKey, new File(outputLocalFile))
         upload.waitForUploadResult()
+      }
     }
     cleanup()
     Exec