Parse Java varargs annotations

rewrite-java-21/src/main/java/org/openrewrite/java/isolated/ReloadableJava21ParserVisitor.java

@@ -1506,9 +1506,22 @@ private TypeTree arrayTypeTree(Tree tree, Map<Integer, JCAnnotation> annotationP
         Space prefix = whitespace();
         TypeTree elemType = convert(typeIdent);
         List<J.Annotation> annotations = leadingAnnotations(annotationPosTable);
-        JLeftPadded<Space> dimension = padLeft(sourceBefore("["), sourceBefore("]"));
+
+        // Check if this is varargs (...) or regular array brackets ([])
+        Markers markers = Markers.EMPTY;
+        JLeftPadded<Space> dimension;
+        int nextNonWhitespace = indexOfNextNonWhitespace(cursor, source);
+        if (source.startsWith("...", nextNonWhitespace)) {
+            // Varargs syntax
+            markers = markers.addIfAbsent(new org.openrewrite.java.marker.Varargs(randomId()));
+            dimension = padLeft(sourceBefore("..."), EMPTY);
+        } else {
+            // Regular array brackets
+            dimension = padLeft(sourceBefore("["), sourceBefore("]"));
+        }
+
         assert arrayTypeTree != null;
-        return new J.ArrayType(randomId(), prefix, Markers.EMPTY,
+        return new J.ArrayType(randomId(), prefix, markers,
                 count == 1 ? elemType : mapDimensions(elemType, arrayTypeTree.getType(), annotationPosTable),
                 annotations,
                 dimension,
@@ -1524,22 +1537,32 @@ private TypeTree mapDimensions(TypeTree baseType, Tree tree, Map<Integer, JCAnno
 
         if (typeIdent instanceof JCArrayTypeTree) {
             List<J.Annotation> annotations = leadingAnnotations(annotationPosTable);
-            int saveCursor = cursor;
-            whitespace();
-            if (source.startsWith("[", cursor)) {
-                cursor = saveCursor;
-                JLeftPadded<Space> dimension = padLeft(sourceBefore("["), sourceBefore("]"));
-                return new J.ArrayType(
-                        randomId(),
-                        EMPTY,
-                        Markers.EMPTY,
-                        mapDimensions(baseType, ((JCArrayTypeTree) typeIdent).elemtype, annotationPosTable),
-                        annotations,
-                        dimension,
-                        typeMapping.type(tree)
-                );
+
+            // Check if this is varargs (...) or regular array brackets ([])
+            Markers markers = Markers.EMPTY;
+            JLeftPadded<Space> dimension;
+            int nextNonWhitespace = indexOfNextNonWhitespace(cursor, source);
+            if (source.startsWith("...", nextNonWhitespace)) {
+                // Varargs syntax
+                markers = markers.addIfAbsent(new org.openrewrite.java.marker.Varargs(randomId()));
+                dimension = padLeft(sourceBefore("..."), EMPTY);
+            } else if (source.startsWith("[", nextNonWhitespace)) {
+                // Regular array brackets
+                dimension = padLeft(sourceBefore("["), sourceBefore("]"));
+            } else {
+                // No dimension found
+                return baseType;
             }
-            cursor = saveCursor;
+
+            return new J.ArrayType(
+                    randomId(),
+                    EMPTY,
+                    markers,
+                    mapDimensions(baseType, ((JCArrayTypeTree) typeIdent).elemtype, annotationPosTable),
+                    annotations,
+                    dimension,
+                    typeMapping.type(tree)
+            );
         }
         return baseType;
     }
@@ -1720,7 +1743,7 @@ private J.VariableDeclarations visitVariables(List<VariableTree> nodes, Space fm
                 }
             }
             int idx = indexOfNextNonWhitespace(elementType.getEndPosition(endPosTable), source);
-            typeExpr = idx != -1 && (source.charAt(idx) == '[' || source.charAt(idx) == '@') ? convert(vartype) :
+            typeExpr = idx != -1 && (source.charAt(idx) == '[' || source.charAt(idx) == '@' || source.startsWith("...", idx)) ? convert(vartype) :
                     // we'll capture the array dimensions in a bit, just convert the element type
                     convert(elementType);
         } else {
@@ -1736,15 +1759,6 @@ private J.VariableDeclarations visitVariables(List<VariableTree> nodes, Space fm
             typeExpr = new J.AnnotatedType(randomId(), prefix, Markers.EMPTY, ListUtils.mapFirst(typeExprAnnotations, a -> a.withPrefix(EMPTY)), typeExpr);
         }
 
-        Space varargs = null;
-        if (typeExpr != null && typeExpr.getMarkers().findFirst(JavaVarKeyword.class).isEmpty()) {
-            int varargStart = indexOfNextNonWhitespace(cursor, source);
-            if (source.startsWith("...", varargStart)) {
-                varargs = format(source, cursor, varargStart);
-                cursor = varargStart + 3;
-            }
-        }
-
         List<JRightPadded<J.VariableDeclarations.NamedVariable>> vars = new ArrayList<>(nodes.size());
         for (int i = 0; i < nodes.size(); i++) {
             JCVariableDecl n = (JCVariableDecl) nodes.get(i);
@@ -1770,7 +1784,7 @@ private J.VariableDeclarations visitVariables(List<VariableTree> nodes, Space fm
             );
         }
 
-        return new J.VariableDeclarations(randomId(), fmt, Markers.EMPTY, modifierResults.getLeadingAnnotations(), modifierResults.getModifiers(), typeExpr, varargs, vars);
+        return new J.VariableDeclarations(randomId(), fmt, Markers.EMPTY, modifierResults.getLeadingAnnotations(), modifierResults.getModifiers(), typeExpr, null, vars);
     }
 
     private List<JLeftPadded<Space>> arrayDimensions() {

rewrite-java-tck/src/main/java/org/openrewrite/java/tree/AnnotationTest.java

@@ -690,4 +690,64 @@ class A {
           )
         );
     }
+
+    @Issue("https://github.com/openrewrite/rewrite/issues/3881")
+    @Test
+    void annotatedVarargs() {
+        rewriteRun(
+          java(
+            """
+              package com.example;
+
+              import org.jspecify.annotations.NonNull;
+
+              class Test {
+                  void method(@NonNull String @NonNull ... args) {
+                  }
+              }
+              """
+          )
+        );
+    }
+
+    @Issue("https://github.com/openrewrite/rewrite/issues/3881")
+    @Test
+    void annotatedVarargsFinal() {
+        rewriteRun(
+          java(
+            """
+              package com.example;
+
+              import org.jspecify.annotations.NonNull;
+
+              class Test {
+                  private String method(@NonNull final String @NonNull... args) {
+                      return "";
+                  }
+              }
+              """
+          )
+        );
+    }
+
+    @Issue("https://github.com/openrewrite/rewrite/issues/3881")
+    @Test
+    void multipleParametersWithAnnotatedVarargs() {
+        rewriteRun(
+          java(
+            """
+              package com.example;
+
+              import org.jspecify.annotations.NonNull;
+
+              class Test {
+                  public static int resolvePoolSize(@NonNull String propertyName, @NonNull String value,
+                          @NonNull String @NonNull... magicValues) {
+                      return 0;
+                  }
+              }
+              """
+          )
+        );
+    }
 }

rewrite-java/src/main/java/org/openrewrite/java/JavaPrinter.java

@@ -22,6 +22,7 @@
 import org.openrewrite.java.marker.CompactConstructor;
 import org.openrewrite.java.marker.OmitParentheses;
 import org.openrewrite.java.marker.TrailingComma;
+import org.openrewrite.java.marker.Varargs;
 import org.openrewrite.java.tree.*;
 import org.openrewrite.java.tree.J.*;
 import org.openrewrite.marker.Marker;
@@ -210,9 +211,15 @@ public J visitArrayType(ArrayType arrayType, PrintOutputCapture<P> p) {
         visit(arrayType.getAnnotations(), p);
         if (arrayType.getDimension() != null) {
             visitSpace(arrayType.getDimension().getBefore(), Space.Location.DIMENSION_PREFIX, p);
-            p.append('[');
-            visitSpace(arrayType.getDimension().getElement(), Space.Location.DIMENSION, p);
-            p.append(']');
+            if (arrayType.getMarkers().findFirst(Varargs.class).isPresent()) {
+                // Print varargs syntax
+                p.append("...");
+            } else {
+                // Print regular array brackets
+                p.append('[');
+                visitSpace(arrayType.getDimension().getElement(), Space.Location.DIMENSION, p);
+                p.append(']');
+            }
 
             if (arrayType.getElementType() instanceof J.ArrayType) {
                 printDimensions((ArrayType) arrayType.getElementType(), p);
@@ -226,9 +233,15 @@ private void printDimensions(J.ArrayType arrayType, PrintOutputCapture<P> p) {
         beforeSyntax(arrayType, Space.Location.ARRAY_TYPE_PREFIX, p);
         visit(arrayType.getAnnotations(), p);
         visitSpace(arrayType.getDimension().getBefore(), Space.Location.DIMENSION_PREFIX, p);
-        p.append('[');
-        visitSpace(arrayType.getDimension().getElement(), Space.Location.DIMENSION, p);
-        p.append(']');
+        if (arrayType.getMarkers().findFirst(Varargs.class).isPresent()) {
+            // Print varargs syntax
+            p.append("...");
+        } else {
+            // Print regular array brackets
+            p.append('[');
+            visitSpace(arrayType.getDimension().getElement(), Space.Location.DIMENSION, p);
+            p.append(']');
+        }
         if (arrayType.getElementType() instanceof J.ArrayType) {
             printDimensions((ArrayType) arrayType.getElementType(), p);
         }

rewrite-java/src/main/java/org/openrewrite/java/marker/Varargs.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2025 the original author or authors.
+ * <p>
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.openrewrite.java.marker;
+
+import lombok.Value;
+import lombok.With;
+import org.openrewrite.marker.Marker;
+
+import java.util.UUID;
+
+/**
+ * Indicates that a {@link org.openrewrite.java.tree.J.ArrayType} represents a varargs parameter type.
+ * When present, the array type should be printed using {@code ...} syntax instead of {@code []}.
+ * <p>
+ * For example, {@code String...} instead of {@code String[]}.
+ */
+@Value
+@With
+public class Varargs implements Marker {
+    UUID id;
+}