--- a/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/LambdaToMethod.java	Wed Jun 17 19:53:48 2020 +0200
+++ b/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/LambdaToMethod.java	Wed Jul 08 09:23:59 2020 -0400
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2010, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -2425,7 +2425,8 @@
 
         @Override
         protected void append(byte[] ba) {
-            sb.append(new String(ba));
+            Name name = names.fromUtf(ba);
+            sb.append(name.toString());
         }
 
         @Override

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/java/lang/invoke/lambda/LambdaFileEncodingSerialization.java	Wed Jul 08 09:23:59 2020 -0400
@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @bug 8248231
+ * @summary Test to verify lambda serialization uses the correct UTF-8 encoding
+ * @library /test/lib
+ * @build jdk.test.lib.JDKToolFinder
+ *        jdk.test.lib.process.ProcessTools
+ * @run testng LambdaFileEncodingSerialization
+ */
+import java.io.File;
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+import java.util.Arrays;
+import java.util.ArrayList;
+
+import org.testng.annotations.Test;
+import static org.testng.Assert.assertTrue;
+
+import jdk.test.lib.JDKToolFinder;
+import jdk.test.lib.process.ProcessTools;
+
+public class LambdaFileEncodingSerialization {
+
+    private static final String TEST_NAME = "TestLambdaFileEncodingSerialization";
+
+    @Test
+    public static void testDeserializeLambdaEncoding() throws Throwable {
+
+        String javac = JDKToolFinder.getTestJDKTool("javac");
+        String java = JDKToolFinder.getTestJDKTool("java");
+
+        String srcDir = System.getProperty("test.src");
+
+        // Compile <TEST_NAME>.java using ISO-8859-1 encoding
+        String opts = "-J-Dfile.encoding=ISO-8859-1 -cp . -d .";
+        String file = srcDir + File.separator + TEST_NAME + ".java";
+        int exitCode = runCmd(javac, opts, file);
+        assertTrue(exitCode == 0, "Command " + javac + " " + opts + " " + file + " , failed exitCode = "+exitCode);
+
+        // Execute TEST_NAME containing the re-serialized lambda
+        opts = "-cp .";
+        file = TEST_NAME;
+        exitCode = runCmd(java, opts, file);
+        assertTrue(exitCode == 0, "Command " + java + " " + opts + " " + file + " , failed exitCode = "+exitCode);
+    }
+
+    // Run a command
+    private static int runCmd(String prog, String options, String file) throws Throwable {
+
+        List<String> argList = new ArrayList<String>();
+        argList.add(prog);
+        argList.addAll(Arrays.asList(options.split(" ")));
+        argList.add(file);
+
+        ProcessBuilder pb = new ProcessBuilder(argList);
+        Map<String, String> env = pb.environment();
+        env.put("LC_ALL", "en_US.UTF-8"); // Ensure locale supports the test requirements, lambda with a UTF char
+
+        int exitCode = ProcessTools.executeCommand(pb).outputTo(System.out)
+                                          .errorTo(System.err)
+                                          .getExitValue();
+        return exitCode;
+    }
+
+}
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/java/lang/invoke/lambda/TestLambdaFileEncodingSerialization.java	Wed Jul 08 09:23:59 2020 -0400
@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.Serializable;
+import java.nio.charset.*;
+import java.util.concurrent.Callable;
+
+/*
+ * Testcase for verifying deserializeLambda containing a non-ASCII mappable char
+ * is correctly handled as UTF-8
+ */
+public class TestLambdaFileEncodingSerialization {
+        public static class ABCâ implements Serializable {
+                public String msg;
+                public ABCâ() {
+                        msg = "Hello world";
+                }
+                public static Callable<ABCâ> getHello() {
+                        return (Callable<ABCâ> & Serializable) () -> {
+                                return new ABCâ();
+                        };
+                }
+        }
+
+    // Re-serialize the object containing the lambda
+    private static <T> T reserialize(T o) throws IOException {
+                ByteArrayOutputStream baos = new ByteArrayOutputStream();
+                ObjectOutputStream oos = new ObjectOutputStream(baos);
+
+                oos.writeObject(o);
+
+                oos.close();
+
+                ObjectInputStream iis = new ObjectInputStream(new ByteArrayInputStream(baos.toByteArray()));
+
+                try {
+                        o = (T)iis.readObject();
+                } catch (ClassNotFoundException e) {
+                        throw new IOException(e);
+                }
+                iis.close();
+                return o;
+    }
+
+    public static void main(String args[]) throws Exception{
+        System.out.println("Default charset = "+Charset.defaultCharset());
+
+        // Construct class containing suitable UTF-8 char
+        Callable<ABCâ> foo = ABCâ.getHello();
+        ABCâ hello = new ABCâ();
+
+        // re-serialize hello
+        ABCâ rh = reserialize(hello);
+        System.out.println(rh.msg);
+
+        // re-serialize foo and call()
+        reserialize(foo).call();
+    }
+}
+