Escape slashes in Java code too

src/main/java/org/openrewrite/java/template/processor/RefasterTemplateProcessor.java

@@ -555,7 +555,7 @@ private String joinPreconditions(Collection<String> preconditions, String op, in
     }
 
     private String escape(String string) {
-        return string.replace("\"", "\\\"").replaceAll("\\R", "\\\\n");
+        return string.replace("\\", "\\\\").replace("\"", "\\\"").replaceAll("\\R", "\\\\n");
     }
 
     private String parameters(TemplateDescriptor descriptor) {

src/test/java/org/openrewrite/java/template/RefasterTemplateProcessorTest.java

@@ -34,6 +34,7 @@
 class RefasterTemplateProcessorTest {
     @ParameterizedTest
     @ValueSource(strings = {
+      "ConstantsFormat",
       "MethodThrows",
       "NestedPreconditions",
       "ParameterReuse",

src/test/resources/refaster/ConstantsFormat.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2023 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 foo;
+
+import com.google.errorprone.refaster.annotation.AfterTemplate;
+import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import com.sun.tools.javac.util.Constants;
+import com.sun.tools.javac.util.Convert;
+
+class ConstantsFormat {
+    @BeforeTemplate
+    String before(String value) {
+        return String.format("\"%s\"", Convert.quote(value));
+    }
+
+    @AfterTemplate
+    String after(String value) {
+        return Constants.format(value);
+    }
+}

src/test/resources/refaster/ConstantsFormatRecipe.java

@@ -0,0 +1,83 @@
+/*
+ * Copyright 2023 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 foo;
+
+import org.openrewrite.ExecutionContext;
+import org.openrewrite.Preconditions;
+import org.openrewrite.Recipe;
+import org.openrewrite.TreeVisitor;
+import org.openrewrite.internal.lang.NonNullApi;
+import org.openrewrite.java.JavaTemplate;
+import org.openrewrite.java.JavaVisitor;
+import org.openrewrite.java.search.*;
+import org.openrewrite.java.template.Primitive;
+import org.openrewrite.java.template.Semantics;
+import org.openrewrite.java.template.function.*;
+import org.openrewrite.java.template.internal.AbstractRefasterJavaVisitor;
+import org.openrewrite.java.tree.*;
+
+import java.util.*;
+
+import static org.openrewrite.java.template.internal.AbstractRefasterJavaVisitor.EmbeddingOption.*;
+
+import com.sun.tools.javac.util.Convert;
+import com.sun.tools.javac.util.Constants;
+
+@NonNullApi
+public class ConstantsFormatRecipe extends Recipe {
+
+    @Override
+    public String getDisplayName() {
+        return "Refaster template `ConstantsFormat`";
+    }
+
+    @Override
+    public String getDescription() {
+        return "Recipe created for the following Refaster template:\n```java\nclass ConstantsFormat {\n    \n    @BeforeTemplate()\n    String before(String value) {\n        return String.format(\"\\\"%s\\\"\", Convert.quote(value));\n    }\n    \n    @AfterTemplate()\n    String after(String value) {\n        return Constants.format(value);\n    }\n}\n```\n.";
+    }
+
+    @Override
+    public TreeVisitor<?, ExecutionContext> getVisitor() {
+        JavaVisitor<ExecutionContext> javaVisitor = new AbstractRefasterJavaVisitor() {
+            final JavaTemplate before = Semantics.expression(this, "before", (String value) -> String.format("\"%s\"", com.sun.tools.javac.util.Convert.quote(value))).build();
+            final JavaTemplate after = Semantics.expression(this, "after", (String value) -> com.sun.tools.javac.util.Constants.format(value)).build();
+
+            @Override
+            public J visitMethodInvocation(J.MethodInvocation elem, ExecutionContext ctx) {
+                JavaTemplate.Matcher matcher;
+                if ((matcher = before.matcher(getCursor())).find()) {
+                    maybeRemoveImport("com.sun.tools.javac.util.Convert");
+                    return embed(
+                            after.apply(getCursor(), elem.getCoordinates().replace(), matcher.parameter(0)),
+                            getCursor(),
+                            ctx,
+                            SHORTEN_NAMES
+                    );
+                }
+                return super.visitMethodInvocation(elem, ctx);
+            }
+
+        };
+        return Preconditions.check(
+                Preconditions.and(
+                        new UsesType<>("com.sun.tools.javac.util.Convert", true),
+                        new UsesMethod<>("java.lang.String format(..)"),
+                        new UsesMethod<>("com.sun.tools.javac.util.Convert quote(..)")
+                ),
+                javaVisitor
+        );
+    }
+}