diff --git a/CHANGES.md b/CHANGES.md
index 95ce8f24c1..02e14cc79a 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -17,6 +17,8 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 * Add explicit support for JSONC / CSS via biome, via the file extensions `.css` and `.jsonc`. 
   ([#2259](https://github.com/diffplug/spotless/pull/2259))
 * Bump default `jackson` version to latest `2.17.2` -> `2.18.0`. ([#2279](https://github.com/diffplug/spotless/pull/2279))
+### Fixed
+* Java import order, ignore duplicate group entries. ([#2293](https://github.com/diffplug/spotless/pull/2293))
 
 ## [3.0.0.BETA2] - 2024-08-25
 ### Changed
diff --git a/lib/src/main/java/com/diffplug/spotless/java/ImportSorterImpl.java b/lib/src/main/java/com/diffplug/spotless/java/ImportSorterImpl.java
index 4d343d41d8..4393de95a3 100644
--- a/lib/src/main/java/com/diffplug/spotless/java/ImportSorterImpl.java
+++ b/lib/src/main/java/com/diffplug/spotless/java/ImportSorterImpl.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2023 DiffPlug
+ * Copyright 2016-2024 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -33,6 +33,7 @@ final class ImportSorterImpl {
 	private static final String SUBGROUP_SEPARATOR = "|";
 
 	private final List<ImportsGroup> importsGroups;
+	private final Set<String> knownGroupings = new HashSet<>();
 	private final Map<String, List<String>> matchingImports = new HashMap<>();
 	private final List<String> notMatching = new ArrayList<>();
 	private final Set<String> allImportOrderItems = new HashSet<>();
@@ -44,10 +45,12 @@ private static class ImportsGroup {
 
 		private final List<String> subGroups;
 
-		public ImportsGroup(String importOrder) {
+		public ImportsGroup(String importOrder, Set<String> knownGroupings) {
 			this.subGroups = Stream.of(importOrder.split("\\" + SUBGROUP_SEPARATOR, -1))
 					.map(this::normalizeStatic)
+					.filter(group -> !knownGroupings.contains(group))
 					.collect(Collectors.toList());
+			knownGroupings.addAll(this.subGroups);
 		}
 
 		private String normalizeStatic(String subgroup) {
@@ -80,7 +83,7 @@ private List<String> sort(List<String> imports, String lineFormat) {
 
 	private ImportSorterImpl(List<String> importOrder, boolean wildcardsLast, boolean semanticSort,
 			Set<String> treatAsPackage, Set<String> treatAsClass) {
-		importsGroups = importOrder.stream().filter(Objects::nonNull).map(ImportsGroup::new).collect(Collectors.toList());
+		importsGroups = importOrder.stream().filter(Objects::nonNull).map(order -> new ImportsGroup(order, knownGroupings)).collect(Collectors.toList());
 		putStaticItemIfNotExists(importsGroups);
 		putCatchAllGroupIfNotExists(importsGroups);
 
@@ -107,13 +110,13 @@ private void putStaticItemIfNotExists(List<ImportsGroup> importsGroups) {
 				indexOfFirstStatic = i;
 			}
 		}
-		importsGroups.add(indexOfFirstStatic, new ImportsGroup(STATIC_KEYWORD));
+		importsGroups.add(indexOfFirstStatic, new ImportsGroup(STATIC_KEYWORD, this.knownGroupings));
 	}
 
 	private void putCatchAllGroupIfNotExists(List<ImportsGroup> importsGroups) {
 		boolean catchAllSubGroupExist = importsGroups.stream().anyMatch(group -> group.getSubGroups().contains(CATCH_ALL_SUBGROUP));
 		if (!catchAllSubGroupExist) {
-			importsGroups.add(new ImportsGroup(CATCH_ALL_SUBGROUP));
+			importsGroups.add(new ImportsGroup(CATCH_ALL_SUBGROUP, this.knownGroupings));
 		}
 	}
 
diff --git a/plugin-gradle/CHANGES.md b/plugin-gradle/CHANGES.md
index ec6f0aea9f..e3550693f7 100644
--- a/plugin-gradle/CHANGES.md
+++ b/plugin-gradle/CHANGES.md
@@ -10,6 +10,8 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
   formatting step. Biome supports formatting CSS as of 1.8.0 (experimental, opt-in) and 1.9.0 (stable).
   ([#2259](https://github.com/diffplug/spotless/pull/2259))
 * Bump default `jackson` version to latest `2.17.2` -> `2.18.0`. ([#2279](https://github.com/diffplug/spotless/pull/2279))
+### Fixed
+* Java import order, ignore duplicate group entries. ([#2293](https://github.com/diffplug/spotless/pull/2293))
 
 ## [7.0.0.BETA2] - 2024-08-25
 ### Changed
diff --git a/plugin-maven/CHANGES.md b/plugin-maven/CHANGES.md
index 4328fc14e1..452e1e79a8 100644
--- a/plugin-maven/CHANGES.md
+++ b/plugin-maven/CHANGES.md
@@ -11,6 +11,8 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
   formatting step. Biome supports formatting CSS as of 1.8.0 (experimental, opt-in) and 1.9.0 (stable).
   ([#2259](https://github.com/diffplug/spotless/pull/2259))
 * Bump default `jackson` version to latest `2.17.2` -> `2.18.0`. ([#2279](https://github.com/diffplug/spotless/pull/2279))
+### Fixed
+* Java import order, ignore duplicate group entries. ([#2293](https://github.com/diffplug/spotless/pull/2293))
 
 ## [2.44.0.BETA2] - 2024-08-25
 ### Changed
diff --git a/testlib/src/test/java/com/diffplug/spotless/java/ImportOrderStepTest.java b/testlib/src/test/java/com/diffplug/spotless/java/ImportOrderStepTest.java
index 75cd984f08..47bdff89dd 100644
--- a/testlib/src/test/java/com/diffplug/spotless/java/ImportOrderStepTest.java
+++ b/testlib/src/test/java/com/diffplug/spotless/java/ImportOrderStepTest.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2023 DiffPlug
+ * Copyright 2016-2024 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -43,6 +43,12 @@ void sortImportsFromArrayWithSubgroups() {
 		StepHarness.forStep(step).testResource("java/importsorter/JavaCodeUnsortedImportsSubgroups.test", "java/importsorter/JavaCodeSortedImportsSubgroups.test");
 	}
 
+	@Test
+	void sortImportsFromArrayWithDuplicateEntries() {
+		FormatterStep step = ImportOrderStep.forJava().createFrom("java|javax", "java", "org|\\#com", "\\#");
+		StepHarness.forStep(step).testResource("java/importsorter/JavaCodeUnsortedImportsSubgroups.test", "java/importsorter/JavaCodeSortedImportsSubgroups.test");
+	}
+
 	@Test
 	void sortImportsFromArrayWithSubgroupsLeadingCatchAll() {
 		FormatterStep step = ImportOrderStep.forJava().createFrom("\\#|");