--- /dev/null	2015-07-25 15:02:20.097409468 -0700
+++ new/test/java/lang/String/CompactString/SubString.java	2015-10-30 14:04:19.909197620 -0700
@@ -0,0 +1,84 @@
+/*
+ * 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 org.testng.annotations.DataProvider;
+import org.testng.annotations.Test;
+
+import static org.testng.Assert.assertEquals;
+
+/*
+ * @test
+ * @bug 8077559
+ * @summary Tests Compact String. This one is for String.subString.
+ * @run testng/othervm -XX:+CompactStrings SubString
+ * @run testng/othervm -XX:-CompactStrings SubString
+ */
+
+public class SubString extends CompactString {
+
+    @DataProvider
+    public Object[][] provider() {
+        return new Object[][] {
+
+                new Object[] { STRING_EMPTY, 0, 0, "" },
+                new Object[] { STRING_L1, 0, 1, "A" },
+                new Object[] { STRING_L1, 1, 1, "" },
+                new Object[] { STRING_L2, 0, 2, "AB" },
+                new Object[] { STRING_L2, 1, 2, "B" },
+                new Object[] { STRING_LLONG, 0, 8, "ABCDEFGH" },
+                new Object[] { STRING_LLONG, 7, 8, "H" },
+                new Object[] { STRING_LLONG, 8, 8, "" },
+                new Object[] { STRING_LLONG, 3, 7, "DEFG" },
+                new Object[] { STRING_U1, 0, 1, "\uFF21" },
+                new Object[] { STRING_U1, 1, 1, "" },
+                new Object[] { STRING_U1, 0, 0, "" },
+                new Object[] { STRING_U2, 0, 2, "\uFF21\uFF22" },
+                new Object[] { STRING_U2, 1, 2, "\uFF22" },
+                new Object[] { STRING_U2, 2, 2, "" },
+                new Object[] { STRING_U2, 0, 2, "\uFF21\uFF22" },
+                new Object[] { STRING_U2, 1, 2, "\uFF22" },
+                new Object[] { STRING_M12, 1, 2, "A" },
+                new Object[] { STRING_M11, 0, 1, "A" },
+                new Object[] { STRING_M11, 1, 2, "\uFF21" },
+                new Object[] { STRING_UDUPLICATE, 1, 5,
+                        "\uFF22\uFF21\uFF22\uFF21" },
+                new Object[] { STRING_MDUPLICATE1, 9, 10, "A" },
+                new Object[] { STRING_MDUPLICATE1, 7, 8, "A" }, };
+    }
+
+    @Test(dataProvider = "provider")
+    public void testSubstring(String str, int beginIndex, int endIndex,
+            String expected) {
+        map.get(str)
+                .forEach(
+                        (source, data) -> {
+                            assertEquals(
+                                    data.substring(beginIndex, endIndex),
+                                    expected,
+                                    String.format(
+                                            "testing String(%s).substring(%d, %d), source : %s, ",
+                                            escapeNonASCIIs(data), beginIndex,
+                                            endIndex, source));
+                        });
+    }
+}