fix(SplitPDF): create immutable list for dynamic additions

src/main/java/stirling/software/SPDF/controller/api/SplitPDFController.java

@@ -51,8 +51,12 @@ public class SplitPDFController {
         PDDocument document = Loader.loadPDF(file.getBytes());
 
         List<Integer> pageNumbers = request.getPageNumbersList(document, true);
-        if (!pageNumbers.contains(document.getNumberOfPages() - 1))
+        if (!pageNumbers.contains(document.getNumberOfPages() - 1)) {
+            // Create a mutable ArrayList so we can add to it
+            pageNumbers = new ArrayList<>(pageNumbers);
             pageNumbers.add(document.getNumberOfPages() - 1);
+        }
+
         logger.info(
                 "Splitting PDF into pages: {}",
                 pageNumbers.stream().map(String::valueOf).collect(Collectors.joining(",")));

src/main/java/stirling/software/SPDF/controller/api/SplitPdfBySectionsController.java

@@ -155,5 +155,4 @@ public class SplitPdfBySectionsController {
 
         return splitDocuments;
     }
-
 }

src/main/java/stirling/software/SPDF/model/ApplicationProperties.java

@@ -277,7 +277,6 @@ public class ApplicationProperties {
                     + enableAlphaFunctionality
                     + "]";
         }
-
     }
 
     public static class Ui {

src/main/java/stirling/software/SPDF/model/Role.java

@@ -20,7 +20,11 @@ public enum Role {
     // 0 API calls per day and 20 web calls
     WEB_ONLY_USER("ROLE_WEB_ONLY_USER", 0, 20, "adminUserSettings.webOnlyUser"),
 
-    INTERNAL_API_USER("STIRLING-PDF-BACKEND-API-USER", Integer.MAX_VALUE, Integer.MAX_VALUE, "adminUserSettings.internalApiUser"),
+    INTERNAL_API_USER(
+            "STIRLING-PDF-BACKEND-API-USER",
+            Integer.MAX_VALUE,
+            Integer.MAX_VALUE,
+            "adminUserSettings.internalApiUser"),
 
     DEMO_USER("ROLE_DEMO_USER", 100, 100, "adminUserSettings.demoUser");