diff --git a/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/formatter/FormatterCommentsBugsTest.java b/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/formatter/FormatterCommentsBugsTest.java
index 070c7d13241..ab817711a8b 100644
--- a/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/formatter/FormatterCommentsBugsTest.java
+++ b/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/formatter/FormatterCommentsBugsTest.java
@@ -7774,4 +7774,45 @@ public void testBug552012d() {
 		"}";
 	formatSource(source);
 }
+/**
+ * https://github.com/eclipse-jdt/eclipse.jdt.core/issues/2127
+ */
+public void testIssue2127a() {
+	setComplianceLevel(CompilerOptions.VERSION_9);
+	String source = """
+		/** This   is   a   header   comment */
+
+		/** This   is   a   module   javadoc */
+		module test{}
+		""";
+	formatSource(source, """
+		/** This   is   a   header   comment */
+
+		/** This is a module javadoc */
+		module test {
+		}
+		""",
+		CodeFormatter.K_MODULE_INFO | CodeFormatter.F_INCLUDE_COMMENTS);
+}
+/**
+ * https://github.com/eclipse-jdt/eclipse.jdt.core/issues/2127
+ */
+public void testIssue2127b() {
+	setComplianceLevel(CompilerOptions.VERSION_9);
+	this.formatterPrefs.comment_format_header = true;
+	String source = """
+		/** This   is   a   header   comment */
+
+		/** This   is   a   module   javadoc */
+		module test{}
+		""";
+	formatSource(source, """
+		/** This is a header comment */
+
+		/** This is a module javadoc */
+		module test {
+		}
+		""",
+		CodeFormatter.K_MODULE_INFO | CodeFormatter.F_INCLUDE_COMMENTS);
+}
 }
diff --git a/org.eclipse.jdt.core/formatter/org/eclipse/jdt/internal/formatter/DefaultCodeFormatter.java b/org.eclipse.jdt.core/formatter/org/eclipse/jdt/internal/formatter/DefaultCodeFormatter.java
index e1847e5bba3..bbe84d5bbca 100644
--- a/org.eclipse.jdt.core/formatter/org/eclipse/jdt/internal/formatter/DefaultCodeFormatter.java
+++ b/org.eclipse.jdt.core/formatter/org/eclipse/jdt/internal/formatter/DefaultCodeFormatter.java
@@ -233,10 +233,11 @@ private List<Token> prepareFormattedCode(String source, int kind) {
 	}
 
 	private void findHeader() {
-		if (this.astRoot instanceof CompilationUnit) {
-			CompilationUnit unit = (CompilationUnit) this.astRoot;
+		if (this.astRoot instanceof CompilationUnit unit) {
 			List<TypeDeclaration> types = unit.types();
-			ASTNode firstElement = types.isEmpty() ? unit.getPackage() : types.get(0);
+			ASTNode firstElement = !types.isEmpty() ? types.get(0)
+					: unit.getModule() != null ? unit.getModule()
+					: unit.getPackage();
 			if (firstElement != null) {
 				int headerEndIndex = this.tokenManager.firstIndexIn(firstElement, -1);
 				this.tokenManager.setHeaderEndIndex(headerEndIndex);