From 2b9dac0c8fc20ebd952baf4674e1c4fc2362c77b Mon Sep 17 00:00:00 2001
From: Artem Bilan <artem.bilan@broadcom.com>
Date: Wed, 8 May 2024 16:11:53 -0400
Subject: [PATCH] Fix NPE in the `AbstractInboundFileSynchronizer` for remote
 dir

Related to: #9129

The `remoteDirectoryPath` might be `null`, so it is not correct to attempt `remoteDirectoryPath.charAt(0)`.
Plus `/null` is not correct path.

* Use `/` for empty remote dir.
* Check for `remoteDirectoryPath != null`

(cherry picked from commit 467c96171e5d25d6542841c7beb8ac2b4fa2fc69)
---
 .../AbstractInboundFileSynchronizer.java          | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/spring-integration-file/src/main/java/org/springframework/integration/file/remote/synchronizer/AbstractInboundFileSynchronizer.java b/spring-integration-file/src/main/java/org/springframework/integration/file/remote/synchronizer/AbstractInboundFileSynchronizer.java
index 285740e664..bffe5e31ca 100644
--- a/spring-integration-file/src/main/java/org/springframework/integration/file/remote/synchronizer/AbstractInboundFileSynchronizer.java
+++ b/spring-integration-file/src/main/java/org/springframework/integration/file/remote/synchronizer/AbstractInboundFileSynchronizer.java
@@ -444,7 +444,7 @@ public abstract class AbstractInboundFileSynchronizer<F>
 		}
 	}
 
-	protected boolean copyFileToLocalDirectory(String remoteDirectoryPath, // NOSONAR
+	protected boolean copyFileToLocalDirectory(@Nullable String remoteDirectoryPath, // NOSONAR
 			@Nullable EvaluationContext localFileEvaluationContext, F remoteFile, File localDirectory,
 			Session<F> session) throws IOException {
 
@@ -503,12 +503,15 @@ public abstract class AbstractInboundFileSynchronizer<F>
 				String host = hostPort.substring(0, colonIndex);
 				String port = hostPort.substring(colonIndex + 1);
 				try {
+					String remoteDir = "/";
+					if (remoteDirectoryPath != null) {
+						remoteDir =
+								remoteDirectoryPath.charAt(0) == '/'
+										? remoteDirectoryPath :
+										'/' + remoteDirectoryPath;
+					}
 					String remoteFileMetadata =
-							new URI(protocol(), null, host, Integer.parseInt(port),
-									remoteDirectoryPath.charAt(0) == '/'
-											? remoteDirectoryPath :
-											'/' + remoteDirectoryPath,
-									null, remoteFileName)
+							new URI(protocol(), null, host, Integer.parseInt(port), remoteDir, null, remoteFileName)
 									.toString();
 					this.remoteFileMetadataStore.put(buildMetadataKey(localFile), remoteFileMetadata);
 				}