--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.jcmd/share/classes/sun/tools/common/PrintStreamPrinter.java	Mon Jul 22 14:40:00 2019 +0200
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2019, 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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.
+ */
+
+package sun.tools.common;
+
+import java.io.BufferedInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.PrintStream;
+import java.util.Arrays;
+
+/**
+ * A helper class which prints the content of input streams to print streams.
+ */
+public class PrintStreamPrinter {
+
+    /**
+     * Reads characters in UTF-8 format from the input stream and prints them
+     * with the given print stream. Closes the input stream before it returns.
+     *
+     * @return The number of printed characters.
+     */
+    public static long drainUTF8(InputStream is, PrintStream ps) throws IOException {
+        long result = 0;
+
+        try (BufferedInputStream bis = new BufferedInputStream(is);
+             InputStreamReader isr = new InputStreamReader(bis, "UTF-8")) {
+            char c[] = new char[256];
+            int n;
+
+            do {
+                n = isr.read(c);
+
+                if (n > 0) {
+                    result += n;
+                    ps.print(n == c.length ? c : Arrays.copyOf(c, n));
+                }
+            } while (n > 0);
+        }
+
+        return result;
+    }
+}

--- a/src/jdk.jcmd/share/classes/sun/tools/jcmd/JCmd.java	Mon Jul 22 10:48:14 2019 +0200
+++ b/src/jdk.jcmd/share/classes/sun/tools/jcmd/JCmd.java	Mon Jul 22 14:40:00 2019 +0200
@@ -25,13 +25,10 @@
 
 package sun.tools.jcmd;
 
+import java.io.IOException;
 import java.io.InputStream;
-import java.io.InputStreamReader;
-import java.io.IOException;
 import java.io.UnsupportedEncodingException;
-import java.util.List;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.Comparator;
 import java.net.URISyntaxException;
 
@@ -42,6 +39,7 @@
 
 import sun.tools.attach.HotSpotVirtualMachine;
 import sun.tools.common.ProcessArgumentMatcher;
+import sun.tools.common.PrintStreamPrinter;
 import sun.tools.jstat.JStatLogger;
 import sun.jvmstat.monitor.Monitor;
 import sun.jvmstat.monitor.MonitoredHost;
@@ -122,23 +120,11 @@
             if (line.trim().equals("stop")) {
                 break;
             }
-            try (InputStream in = hvm.executeJCmd(line);
-                 InputStreamReader isr = new InputStreamReader(in, "UTF-8")) {
-                // read to EOF and just print output
-                char c[] = new char[256];
-                int n;
-                boolean messagePrinted = false;
-                do {
-                    n = isr.read(c);
-                    if (n > 0) {
-                        String s = new String(c, 0, n);
-                        System.out.print(s);
-                        messagePrinted = true;
-                    }
-                } while (n > 0);
-                if (!messagePrinted) {
-                    System.out.println("Command executed successfully");
-                }
+
+            InputStream is = hvm.executeJCmd(line);
+
+            if (PrintStreamPrinter.drainUTF8(is, System.out) == 0) {
+                System.out.println("Command executed successfully");
             }
         }
         vm.detach();

--- a/src/jdk.jcmd/share/classes/sun/tools/jinfo/JInfo.java	Mon Jul 22 10:48:14 2019 +0200
+++ b/src/jdk.jcmd/share/classes/sun/tools/jinfo/JInfo.java	Mon Jul 22 14:40:00 2019 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2006, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2006, 2019, 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
@@ -30,10 +30,10 @@
 import java.util.Collection;
 
 import com.sun.tools.attach.VirtualMachine;
-import com.sun.tools.attach.VirtualMachineDescriptor;
 
 import sun.tools.attach.HotSpotVirtualMachine;
 import sun.tools.common.ProcessArgumentMatcher;
+import sun.tools.common.PrintStreamPrinter;
 
 /*
  * This class is the main class for the JInfo utility. It parses its arguments
@@ -203,17 +203,7 @@
 
     // Read the stream from the target VM until EOF, then detach
     private static void drain(VirtualMachine vm, InputStream in) throws IOException {
-        // read to EOF and just print output
-        byte b[] = new byte[256];
-        int n;
-        do {
-            n = in.read(b);
-            if (n > 0) {
-                String s = new String(b, 0, n, "UTF-8");
-                System.out.print(s);
-            }
-        } while (n > 0);
-        in.close();
+        PrintStreamPrinter.drainUTF8(in, System.out);
         vm.detach();
     }
 

--- a/src/jdk.jcmd/share/classes/sun/tools/jstack/JStack.java	Mon Jul 22 10:48:14 2019 +0200
+++ b/src/jdk.jcmd/share/classes/sun/tools/jstack/JStack.java	Mon Jul 22 14:40:00 2019 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2005, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2019, 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
@@ -29,9 +29,9 @@
 import java.util.Collection;
 
 import com.sun.tools.attach.VirtualMachine;
-import com.sun.tools.attach.VirtualMachineDescriptor;
 import sun.tools.attach.HotSpotVirtualMachine;
 import sun.tools.common.ProcessArgumentMatcher;
+import sun.tools.common.PrintStreamPrinter;
 
 /*
  * This class is the main class for the JStack utility. It parses its arguments
@@ -128,18 +128,8 @@
         // Cast to HotSpotVirtualMachine as this is implementation specific
         // method.
         InputStream in = ((HotSpotVirtualMachine)vm).remoteDataDump((Object[])args);
-
         // read to EOF and just print output
-        byte b[] = new byte[256];
-        int n;
-        do {
-            n = in.read(b);
-            if (n > 0) {
-                String s = new String(b, 0, n, "UTF-8");
-                System.out.print(s);
-            }
-        } while (n > 0);
-        in.close();
+        PrintStreamPrinter.drainUTF8(in, System.out);
         vm.detach();
     }
 

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/sun/tools/jcmd/JcmdOutputEncodingTest.java	Mon Jul 22 14:40:00 2019 +0200
@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2019, 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.util.Arrays;
+
+import jdk.test.lib.process.OutputAnalyzer;
+import jdk.test.lib.process.ProcessTools;
+import jdk.test.lib.JDKToolLauncher;
+
+/*
+ * @test
+ * @bug 8222491
+ * @summary Tests if we handle the encoding of jcmd output correctly.
+ * @library /test/lib
+ * @run main JcmdOutputEncodingTest
+ */
+public class JcmdOutputEncodingTest {
+
+    public static void main(String[] args) throws Exception {
+        testThreadDump();
+    }
+
+    private static void testThreadDump() throws Exception {
+        String markerName = "markerName" + "\u00e4\u0bb5".repeat(10_000);
+        Thread.currentThread().setName(markerName);
+
+        JDKToolLauncher launcher = JDKToolLauncher.createUsingTestJDK("jcmd");
+        launcher.addToolArg(Long.toString(ProcessTools.getProcessId()));
+        launcher.addToolArg("Thread.print");
+
+        ProcessBuilder processBuilder = new ProcessBuilder();
+        processBuilder.command(launcher.getCommand());
+        OutputAnalyzer output = ProcessTools.executeProcess(processBuilder);
+        output.shouldHaveExitValue(0);
+        output.shouldContain(markerName);
+    }
+}

--- a/test/jdk/sun/tools/jstack/BasicJStackTest.java	Mon Jul 22 10:48:14 2019 +0200
+++ b/test/jdk/sun/tools/jstack/BasicJStackTest.java	Mon Jul 22 14:40:00 2019 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2005, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2019, 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
@@ -36,6 +36,7 @@
 public class BasicJStackTest {
 
     private static ProcessBuilder processBuilder = new ProcessBuilder();
+    private static String markerName = "markerName" + "\u00e4\u0bb5".repeat(10_000);
 
     public static void main(String[] args) throws Exception {
         testJstackNoArgs();
@@ -45,14 +46,17 @@
     private static void testJstackNoArgs() throws Exception {
         OutputAnalyzer output = jstack();
         output.shouldHaveExitValue(0);
+        output.shouldContain(markerName);
     }
 
     private static void testJstack_l() throws Exception {
         OutputAnalyzer output = jstack("-l");
         output.shouldHaveExitValue(0);
+        output.shouldContain(markerName);
     }
 
     private static OutputAnalyzer jstack(String... toolArgs) throws Exception {
+        Thread.currentThread().setName(markerName);
         JDKToolLauncher launcher = JDKToolLauncher.createUsingTestJDK("jstack");
         launcher.addVMArg("-XX:+UsePerfData");
         if (toolArgs != null) {