--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/java/lang/String/CompactString/VMOptionsTest.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2015, 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.*;
+import java.lang.reflect.Field;
+
+import org.testng.annotations.BeforeClass;
+import org.testng.annotations.DataProvider;
+import org.testng.annotations.Test;
+
+import static org.testng.Assert.*;
+
+/*
+ * @test
+ * @bug 8077559
+ * @summary Tests Compact String. This one is testing
+ *          if Compact String enable/disable VM Options is indeed working in String class,
+ *          it's verified by testing if the VM option affect coder and
+ *          COMPACT_STRINGS field in String class.
+ * @modules java.base/java.lang:open
+ * @run testng/othervm -XX:+CompactStrings -DCompactStringEnabled=true VMOptionsTest
+ * @run testng/othervm -XX:-CompactStrings -DCompactStringEnabled=false VMOptionsTest
+ */
+
+public class VMOptionsTest {
+    boolean compactStringEnabled;
+    // corresponding "COMPACT_STRINGS" field in String class.
+    Field COMPACT_STRINGS;
+    // corresponding "coder" field in String class.
+    Field coder;
+
+    // corresponding coder type in String class.
+    final byte LATIN1 = 0;
+    final byte UTF16  = 1;
+
+    @BeforeClass
+    public void setUp() throws Exception {
+        compactStringEnabled = Boolean.valueOf(System.getProperty("CompactStringEnabled", null));
+        COMPACT_STRINGS = String.class.getDeclaredField("COMPACT_STRINGS");
+        COMPACT_STRINGS.setAccessible(true);
+        coder = String.class.getDeclaredField("coder");
+        coder.setAccessible(true);
+    }
+
+    @DataProvider
+    public Object[][] provider() {
+        return new Object[][] {
+                new Object[] {"", LATIN1},
+                new Object[] {"abc", LATIN1},
+                new Object[] {"A\uff21", UTF16},
+                new Object[] {"\uff21\uff22", UTF16}
+        };
+    }
+
+    /*
+     * verify the coder field in String objects.
+     */
+    @Test(dataProvider = "provider")
+    public void testCoder(String str, byte expected) throws Exception {
+        byte c = (byte) coder.get(str);
+        expected = compactStringEnabled ? expected : UTF16;
+        assertEquals(c, expected);
+    }
+
+    /*
+     * verify the COMPACT_STRINGS flag in String objects.
+     */
+    @Test(dataProvider = "provider")
+    public void testCompactStringFlag(String str, byte ignore) throws Exception {
+        assertTrue(COMPACT_STRINGS.get(str).equals(compactStringEnabled));
+    }
+}