1 /*
   2  * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 import sun.hotspot.WhiteBox;
  26 
  27 public class InternStringTest {
  28     public static String passed_output1 = "Found shared string.";
  29     public static String passed_output2 = "Shared strings are equal.";
  30     public static String passed_output3 = "Found shared string containing latin1 supplement chars.";
  31     public static String passed_output4 = "Found shared string containing non-western chars.";
  32     public static final String latin1Sup  = "XXXX \u00a3 YYYY"; // \u00a3 = The pound sign
  33     public static final String nonWestern = "XXXX \u5678 YYYY"; // \u5678 = Unicode Han Character 'ton (metric or English)'
  34 
  35     public static void main(String[] args) throws Exception {
  36         WhiteBox wb = WhiteBox.getWhiteBox();
  37 
  38         // All string literals are shared.
  39         String shared1 = "LiveOak";
  40         String interned1 = shared1.intern();
  41         if (wb.areSharedStringsIgnored() || wb.isShared(interned1)) {
  42             System.out.println(passed_output1);
  43         } else {
  44             throw new RuntimeException("Failed: String is not shared.");
  45         }
  46 
  47         // Test 2: shared_string1.intern() == shared_string2.intern()
  48         String shared2 = "LiveOak";
  49         String interned2 = shared2.intern();
  50         if (interned1 == interned2) {
  51             System.out.println(passed_output2);
  52         } else {
  53             throw new RuntimeException("Not equal!");
  54         }
  55 
  56         // Test 3: interned strings with a char in latin1 supplement block [\u0080-\u00ff]
  57         {
  58             String a = "X" + latin1Sup.substring(1);
  59             String b = a.intern();
  60 
  61             if (wb.areSharedStringsIgnored() || wb.isShared(b)) {
  62                 System.out.println(passed_output3);
  63             } else {
  64                 throw new RuntimeException("Failed: expected shared string with latin1-supplement chars.");
  65             }
  66         }
  67 
  68         // Test 5: interned strings with non-western characters
  69         {
  70             String a = "X" + nonWestern.substring(1);
  71             String b = a.intern();
  72             if (wb.areSharedStringsIgnored() || wb.isShared(b)) {
  73                 System.out.println(passed_output4);
  74             } else {
  75                 throw new RuntimeException("Failed: expected shared string with non-western chars.");
  76             }
  77         }
  78     }
  79 }