--- a/test/jdk/sun/tools/jcmd/JcmdOutputEncodingTest.java	Mon Jul 29 08:17:26 2019 +0000
+++ b/test/jdk/sun/tools/jcmd/JcmdOutputEncodingTest.java	Fri Jul 26 10:52:47 2019 +0200
@@ -22,6 +22,8 @@
  */
 
 import java.util.Arrays;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
 
 import jdk.test.lib.process.OutputAnalyzer;
 import jdk.test.lib.process.ProcessTools;
@@ -41,17 +43,19 @@
     }
 
     private static void testThreadDump() throws Exception {
-        String markerName = "markerName" + "\u00e4\u0bb5".repeat(10_000);
-        Thread.currentThread().setName(markerName);
+        String marker = "markerName" + "\u00e4\u0bb5".repeat(60);
+        Charset cs = StandardCharsets.UTF_8;
+        Thread.currentThread().setName(marker);
 
         JDKToolLauncher launcher = JDKToolLauncher.createUsingTestJDK("jcmd");
+        launcher.addVMArg("-Dfile.encoding=" + cs);
         launcher.addToolArg(Long.toString(ProcessTools.getProcessId()));
         launcher.addToolArg("Thread.print");
 
         ProcessBuilder processBuilder = new ProcessBuilder();
         processBuilder.command(launcher.getCommand());
-        OutputAnalyzer output = ProcessTools.executeProcess(processBuilder);
+        OutputAnalyzer output = ProcessTools.executeProcess(processBuilder, null, cs);
         output.shouldHaveExitValue(0);
-        output.shouldContain(markerName);
+        output.shouldContain(marker);
     }
 }

--- a/test/jdk/sun/tools/jstack/BasicJStackTest.java	Mon Jul 29 08:17:26 2019 +0000
+++ b/test/jdk/sun/tools/jstack/BasicJStackTest.java	Fri Jul 26 10:52:47 2019 +0200
@@ -22,6 +22,8 @@
  */
 
 import java.util.Arrays;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
 
 import jdk.test.lib.process.OutputAnalyzer;
 import jdk.test.lib.process.ProcessTools;
@@ -36,29 +38,40 @@
 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();
         testJstack_l();
+        testJstackUTF8Encoding();
     }
 
     private static void testJstackNoArgs() throws Exception {
-        OutputAnalyzer output = jstack();
+        String marker = "testJstackNoArgs";
+        OutputAnalyzer output = jstack(marker);
         output.shouldHaveExitValue(0);
-        output.shouldContain(markerName);
+        output.shouldContain(marker);
     }
 
     private static void testJstack_l() throws Exception {
-        OutputAnalyzer output = jstack("-l");
+        String marker = "testJstack_l";
+        OutputAnalyzer output = jstack(marker, "-l");
         output.shouldHaveExitValue(0);
-        output.shouldContain(markerName);
+        output.shouldContain(marker);
     }
 
-    private static OutputAnalyzer jstack(String... toolArgs) throws Exception {
-        Thread.currentThread().setName(markerName);
+    private static void testJstackUTF8Encoding() throws Exception {
+        String marker = "markerName" + "\u00e4\u0bb5".repeat(60);
+        OutputAnalyzer output = jstack(marker);
+        output.shouldHaveExitValue(0);
+        output.shouldContain(marker);
+    }
+
+    private static OutputAnalyzer jstack(String marker, String... toolArgs) throws Exception {
+        Charset cs = StandardCharsets.UTF_8;
+        Thread.currentThread().setName(marker);
         JDKToolLauncher launcher = JDKToolLauncher.createUsingTestJDK("jstack");
         launcher.addVMArg("-XX:+UsePerfData");
+        launcher.addVMArg("-Dfile.encoding=" + cs);
         if (toolArgs != null) {
             for (String toolArg : toolArgs) {
                 launcher.addToolArg(toolArg);
@@ -68,7 +81,7 @@
 
         processBuilder.command(launcher.getCommand());
         System.out.println(Arrays.toString(processBuilder.command().toArray()).replace(",", ""));
-        OutputAnalyzer output = ProcessTools.executeProcess(processBuilder);
+        OutputAnalyzer output = ProcessTools.executeProcess(processBuilder, null, cs);
         System.out.println(output.getOutput());
 
         return output;

--- a/test/lib/jdk/test/lib/process/OutputAnalyzer.java	Mon Jul 29 08:17:26 2019 +0000
+++ b/test/lib/jdk/test/lib/process/OutputAnalyzer.java	Fri Jul 26 10:52:47 2019 +0200
@@ -27,6 +27,7 @@
 
 import java.io.IOException;
 import java.io.PrintStream;
+import java.nio.charset.Charset;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.Arrays;
@@ -43,6 +44,18 @@
      * value from a Process
      *
      * @param process Process to analyze
+     * @param cs The charset used to convert stdout/stderr from bytes to chars
+     *           or null for the default charset.
+     * @throws IOException If an I/O error occurs.
+     */
+    public OutputAnalyzer(Process process, Charset cs) throws IOException {
+        buffer = OutputBuffer.of(process, cs);
+    }
+    /**
+     * Create an OutputAnalyzer, a utility class for verifying output and exit
+     * value from a Process
+     *
+     * @param process Process to analyze
      * @throws IOException If an I/O error occurs.
      */
     public OutputAnalyzer(Process process) throws IOException {

--- a/test/lib/jdk/test/lib/process/OutputBuffer.java	Mon Jul 29 08:17:26 2019 +0000
+++ b/test/lib/jdk/test/lib/process/OutputBuffer.java	Fri Jul 26 10:52:47 2019 +0200
@@ -25,6 +25,7 @@
 
 import java.io.ByteArrayOutputStream;
 import java.io.InputStream;
+import java.nio.charset.Charset;
 import java.time.Instant;
 import java.util.concurrent.CancellationException;
 import java.util.concurrent.ExecutionException;
@@ -53,8 +54,12 @@
   public String getStderr();
   public int getExitValue();
 
+  public static OutputBuffer of(Process p, Charset cs) {
+    return new LazyOutputBuffer(p, cs);
+  }
+
   public static OutputBuffer of(Process p) {
-    return new LazyOutputBuffer(p);
+    return new LazyOutputBuffer(p, null);
   }
 
   public static OutputBuffer of(String stdout, String stderr, int exitValue) {
@@ -69,16 +74,18 @@
     private static class StreamTask {
       private final ByteArrayOutputStream buffer;
       private final Future<Void> future;
+      private final Charset cs;
 
-      private StreamTask(InputStream stream) {
+      private StreamTask(InputStream stream, Charset cs) {
         this.buffer = new ByteArrayOutputStream();
+        this.cs = cs;
         this.future = new StreamPumper(stream, buffer).process();
       }
 
       public String get() {
         try {
           future.get();
-          return buffer.toString();
+          return cs == null ? buffer.toString() : buffer.toString(cs);
         } catch (InterruptedException e) {
           Thread.currentThread().interrupt();
           throw new OutputBufferException(e);
@@ -98,11 +105,11 @@
         System.out.flush();
     }
 
-    private LazyOutputBuffer(Process p) {
+    private LazyOutputBuffer(Process p, Charset cs) {
       this.p = p;
       logProgress("Gathering output");
-      outTask = new StreamTask(p.getInputStream());
-      errTask = new StreamTask(p.getErrorStream());
+      outTask = new StreamTask(p.getInputStream(), cs);
+      errTask = new StreamTask(p.getErrorStream(), cs);
     }
 
     @Override

--- a/test/lib/jdk/test/lib/process/ProcessTools.java	Mon Jul 29 08:17:26 2019 +0000
+++ b/test/lib/jdk/test/lib/process/ProcessTools.java	Fri Jul 26 10:52:47 2019 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013, 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
@@ -27,6 +27,7 @@
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.io.PrintStream;
+import java.nio.charset.Charset;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -359,6 +360,21 @@
      * @return The {@linkplain OutputAnalyzer} instance wrapping the process.
      */
     public static OutputAnalyzer executeProcess(ProcessBuilder pb, String input) throws Exception {
+        return executeProcess(pb, null, null);
+    }
+
+    /**
+     * Executes a process, pipe some text into its STDIN, waits for it
+     * to finish and returns the process output. The process will have exited
+     * before this method returns.
+     * @param pb The ProcessBuilder to execute.
+     * @param input The text to pipe into STDIN. Can be null.
+     * @param cs The charset used to convert from bytes to chars or null for
+     *           the default charset.
+     * @return The {@linkplain OutputAnalyzer} instance wrapping the process.
+     */
+    public static OutputAnalyzer executeProcess(ProcessBuilder pb, String input,
+            Charset cs) throws Exception {
         OutputAnalyzer output = null;
         Process p = null;
         boolean failed = false;
@@ -370,7 +386,7 @@
                }
             }
 
-            output = new OutputAnalyzer(p);
+            output = new OutputAnalyzer(p, cs);
             p.waitFor();
 
             return output;