--- /dev/null	2013-07-03 08:19:57.063357762 -0700
+++ new/test/java/util/StringJoiner/MergeTest.java	2013-07-03 14:07:38.190987085 -0700
@@ -0,0 +1,124 @@
+/*
+ * Copyright (c) 2013, 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 8017231
+ * @summary test  StringJoiner::merge
+ * @run testng MergeTest
+ */
+
+import java.util.StringJoiner;
+import java.util.stream.Stream;
+import org.testng.annotations.Test;
+import static org.testng.Assert.assertEquals;
+import static org.testng.Assert.fail;
+
+@Test
+public class MergeTest {
+    public void testNull() {
+        StringJoiner sj = new StringJoiner(",", "{", "}");
+        try {
+            sj.merge(null);
+            fail("Should throw NullPointerException!");
+        } catch (NullPointerException npe) {
+            // expected
+        }
+    }
+
+    public void testSimple() {
+        StringJoiner sj = new StringJoiner(",", "{", "}");
+        StringJoiner other = new StringJoiner(",", "[", "]");
+        Stream.of("a", "b", "c").forEachOrdered(sj::add);
+        Stream.of("d", "e", "f").forEachOrdered(other::add);
+
+        sj.merge(other);
+        assertEquals(sj.toString(), "{a,b,c,d,e,f}");
+    }
+
+    public void testEmptyOther() {
+        StringJoiner sj = new StringJoiner(",", "{", "}");
+        StringJoiner other = new StringJoiner(",", "[", "]");
+        Stream.of("a", "b", "c").forEachOrdered(sj::add);
+
+        sj.merge(other);
+        assertEquals(sj.toString(), "{a,b,c}");
+
+        other.setEmptyValue("EMPTY");
+        sj.merge(other);
+        assertEquals(sj.toString(), "{a,b,c}");
+    }
+
+    public void testEmptyThis() {
+        StringJoiner sj = new StringJoiner(",", "{", "}");
+        StringJoiner other = new StringJoiner(":", "[", "]");
+        Stream.of("d", "e", "f").forEachOrdered(other::add);
+
+        sj.merge(other);
+        assertEquals(sj.toString(), "{d:e:f}");
+
+        sj = new StringJoiner(",", "{", "}").setEmptyValue("EMPTY");
+        assertEquals(sj.toString(), "EMPTY");
+        sj.merge(other);
+        assertEquals(sj.toString(), "{d:e:f}");
+    }
+
+    public void testEmptyBoth() {
+        StringJoiner sj = new StringJoiner(",", "{", "}");
+        StringJoiner other = new StringJoiner(":", "[", "]");
+
+        sj.merge(other);
+        assertEquals(sj.toString(), "{}");
+
+        other.setEmptyValue("NOTHING");
+        sj.merge(other);
+        assertEquals(sj.toString(), "{}");
+
+        sj = new StringJoiner(",", "{", "}").setEmptyValue("EMPTY");
+        assertEquals(sj.toString(), "EMPTY");
+        sj.merge(other);
+        assertEquals(sj.toString(), "EMPTY");
+    }
+
+    public void testCascadeEmpty() {
+        StringJoiner sj = new StringJoiner(",", "{", "}");
+        StringJoiner o1 = new StringJoiner(":", "[", "]").setEmptyValue("Empty1");
+        StringJoiner o2 = new StringJoiner(",", "<", ">").setEmptyValue("Empty2");
+
+        o1.merge(o2);
+        assertEquals(o1.toString(), "Empty1");
+
+        sj.merge(o1);
+        assertEquals(sj.toString(), "{}");
+    }
+
+    public void testDelimiter() {
+        StringJoiner sj = new StringJoiner(",", "{", "}");
+        StringJoiner other = new StringJoiner(":", "[", "]");
+        Stream.of("a", "b", "c").forEachOrdered(sj::add);
+        Stream.of("d", "e", "f").forEachOrdered(other::add);
+
+        sj.merge(other);
+        assertEquals(sj.toString(), "{a,b,c,d:e:f}");
+    }
+}
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