Merge pull request #39856 from yokotaso

* pr/39856:
  Fix possible NullPointerException from getPermission()

Closes gh-39856

spring-boot-project/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/net/protocol/jar/JarUrlConnection.java

@@ -172,7 +172,7 @@ public Object getContent() throws IOException {
 
 	@Override
 	public Permission getPermission() throws IOException {
-		return this.jarFileConnection.getPermission();
+		return (this.jarFileConnection != null) ? this.jarFileConnection.getPermission() : null;
 	}
 
 	@Override