Remove illegal semicolons in Java 21 (#404)

Fixes #396

src/main/java/org/openrewrite/java/migrate/RemoveIllegalSemicolons.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2024 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.migrate;
+
+import org.openrewrite.ExecutionContext;
+import org.openrewrite.Preconditions;
+import org.openrewrite.Recipe;
+import org.openrewrite.TreeVisitor;
+import org.openrewrite.java.JavaIsoVisitor;
+import org.openrewrite.java.search.UsesJavaVersion;
+import org.openrewrite.java.tree.J;
+
+public class RemoveIllegalSemicolons extends Recipe {
+    @Override
+    public String getDisplayName() {
+        return "Remove illegal semicolons";
+    }
+
+    @Override
+    public String getDescription() {
+        //language=markdown
+        return "Remove semicolons after package declarations and imports, no longer accepted in Java 21 as of " +
+               "[JDK-8027682](https://bugs.openjdk.org/browse/JDK-8027682).";
+    }
+
+    @Override
+    public TreeVisitor<?, ExecutionContext> getVisitor() {
+        return Preconditions.check(new UsesJavaVersion<>(21), new JavaIsoVisitor<ExecutionContext>() {
+            @Override
+            public J.Import visitImport(J.Import _import, ExecutionContext ctx) {
+                J.Import im = super.visitImport(_import, ctx);
+                if (im.getPrefix().getWhitespace().contains(";")) {
+                    im = im.withPrefix(im.getPrefix()
+                            .withWhitespace(im.getPrefix().getWhitespace()
+                                    .replaceAll("\\s*;(\\R?)\\s*", "$1")));
+                }
+                return im;
+            }
+        });
+    }
+}

src/main/resources/META-INF/rewrite/java-version-21.yml

@@ -26,6 +26,7 @@ tags:
 recipeList:
   - org.openrewrite.java.migrate.UpgradeToJava17
   - org.openrewrite.java.migrate.JavaVersion21
+  - org.openrewrite.java.migrate.RemoveIllegalSemicolons
   - org.openrewrite.java.migrate.lang.ThreadStopUnsupported
   - org.openrewrite.java.migrate.net.URLConstructorsToURIRecipes
   - org.openrewrite.java.migrate.util.SequencedCollection

src/test/java/org/openrewrite/java/migrate/RemoveIllegalSemicolonsTest.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2024 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.migrate;
+
+import org.junit.jupiter.api.Test;
+import org.openrewrite.Issue;
+import org.openrewrite.test.RecipeSpec;
+import org.openrewrite.test.RewriteTest;
+
+import static org.openrewrite.java.Assertions.java;
+import static org.openrewrite.java.Assertions.javaVersion;
+
+class RemoveIllegalSemicolonsTest implements RewriteTest {
+    @Override
+    public void defaults(RecipeSpec spec) {
+        spec.recipe(new RemoveIllegalSemicolons())
+          .allSources(src -> src.markers(javaVersion(21)));
+    }
+
+    @Test
+    @Issue("https://github.com/openrewrite/rewrite-migrate-java/issues/396")
+    void importSemicolon() {
+        //language=java
+        rewriteRun(
+          java(
+            """
+              package p; ;
+              ;; import java.util.List;
+              class AfterPackage { }
+              """,
+            """
+              package p;
+              import java.util.List;
+              class AfterPackage { }
+              """
+          ),
+          java(
+            """
+              package p;
+              import java.util.List; ;
+              ;; import java.util.Set;
+              class BetweenImport { }
+              """,
+            """
+              package p;
+              import java.util.List;
+              import java.util.Set;
+              class BetweenImport { }
+              """
+          )
+        );
+    }
+}