--- a/src/jdk.internal.le/share/classes/jdk/internal/org/jline/terminal/impl/ExecPty.java	Wed Jun 12 17:22:11 2019 -0700
+++ b/src/jdk.internal.le/share/classes/jdk/internal/org/jline/terminal/impl/ExecPty.java	Thu Jun 13 08:42:47 2019 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2002-2016, the original author or authors.
+ * Copyright (c) 2002-2019, the original author or authors.
  *
  * This software is distributable under the BSD license. See the terms of the
  * BSD license in the documentation provided with this software.
@@ -140,6 +140,9 @@
             if (attr.getControlChar(cchar) != current.getControlChar(cchar)) {
                 String str = "";
                 int v = attr.getControlChar(cchar);
+                if (v == -1) { // Skip if ControlChar is <UNDEF>
+                    continue;
+                }
                 commands.add(cchar.name().toLowerCase().substring(1));
                 if (cchar == ControlChar.VMIN || cchar == ControlChar.VTIME) {
                     commands.add(Integer.toBinaryString(v));

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/langtools/jdk/jshell/ExecPtyGetFlagsToSetTest.java	Thu Jun 13 08:42:47 2019 +0200
@@ -0,0 +1,70 @@
+/*
+ * 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.
+ */
+
+/*
+ * @test
+ * @bug 8224184
+ * @summary Control Char <UNDEF> check for pty
+ * @modules jdk.internal.le/jdk.internal.org.jline.terminal
+ *          jdk.internal.le/jdk.internal.org.jline.terminal.impl
+ * @requires (os.family == "linux") | (os.family == "aix")
+ */
+
+import java.util.List;
+import jdk.internal.org.jline.terminal.Attributes;
+import jdk.internal.org.jline.terminal.Attributes.ControlChar;
+import jdk.internal.org.jline.terminal.Attributes.LocalFlag;
+import jdk.internal.org.jline.terminal.impl.ExecPty;
+
+public class ExecPtyGetFlagsToSetTest extends ExecPty {
+    public ExecPtyGetFlagsToSetTest(String name, boolean system) {
+        super(name, system);
+    }
+
+    @Override
+    protected List<String> getFlagsToSet(Attributes attr, Attributes current) {
+        return super.getFlagsToSet(attr, current);
+    }
+
+    public static void main(String[] args) {
+        ExecPtyGetFlagsToSetTest testPty =
+            new ExecPtyGetFlagsToSetTest("stty", true);
+
+        Attributes attr = new Attributes();
+        Attributes current = new Attributes();
+
+        current.setLocalFlag(LocalFlag.ICANON, false);
+        current.setControlChar(ControlChar.VMIN, 1);
+        current.setControlChar(ControlChar.VTIME, 0);
+
+        attr.setLocalFlag(LocalFlag.ICANON, true);
+        attr.setControlChar(ControlChar.VMIN, -1);
+        attr.setControlChar(ControlChar.VTIME, -1);
+
+        List<String> commands = testPty.getFlagsToSet(attr, current);
+        String result = String.join(" ", commands);
+        if (!result.equals("icanon")) {
+            throw new RuntimeException("stty options contains invalid value.");
+        }
+    }
+}