Add test to detect class load order issues and fix load order bug in lua string class.

src/core/org/luaj/vm2/LuaString.java

@@ -99,8 +99,10 @@ public class LuaString extends LuaValue {
 	 * that have been recently constructed.  If a string is being constructed frequently 
 	 * from different contexts, it will generally show up as a cache hit and resolve 
 	 * to the same value.  */
-	private static final LuaString recent_short_strings[] = 
-			new LuaString[RECENT_STRINGS_CACHE_SIZE];
+	private static final class RecentShortStrings {
+		private static final LuaString recent_short_strings[] = 
+				new LuaString[RECENT_STRINGS_CACHE_SIZE];
+	}
 
 	/**
 	 * Get a {@link LuaString} instance whose bytes match 
@@ -132,10 +134,10 @@ public class LuaString extends LuaValue {
 			return valueFromCopy(bytes, off, len);
 		final int hash = hashCode(bytes, off, len);
 		final int bucket = hash & (RECENT_STRINGS_CACHE_SIZE - 1);
-		final LuaString t = recent_short_strings[bucket];
+		final LuaString t = RecentShortStrings.recent_short_strings[bucket];
 		if (t != null && t.m_hashcode == hash && t.byteseq(bytes, off, len)) return t;
 		final LuaString s = valueFromCopy(bytes, off, len);
-		recent_short_strings[bucket] = s;
+		RecentShortStrings.recent_short_strings[bucket] = s;
 		return s;
 	}
 
@@ -161,10 +163,10 @@ public class LuaString extends LuaValue {
 			return new LuaString(bytes, off, len);
 		final int hash = hashCode(bytes, off, len);
 		final int bucket = hash & (RECENT_STRINGS_CACHE_SIZE - 1);
-		final LuaString t = recent_short_strings[bucket];
+		final LuaString t = RecentShortStrings.recent_short_strings[bucket];
 		if (t != null && t.m_hashcode == hash && t.byteseq(bytes, off, len)) return t;
 		final LuaString s = new LuaString(bytes, off, len);
-		recent_short_strings[bucket] = s;
+		RecentShortStrings.recent_short_strings[bucket] = s;
 		return s;
 	}
 

test/junit/org/luaj/vm2/AllTests.java

@@ -52,6 +52,7 @@ public class AllTests {
 		vm.addTestSuite(StringTest.class);
 		vm.addTestSuite(OrphanedThreadTest.class);
 		vm.addTestSuite(VarargsTest.class);
+		vm.addTestSuite(LoadOrderTest.class);
 		suite.addTest(vm);
 
 		// table tests

test/junit/org/luaj/vm2/LoadOrderTest.java

@@ -0,0 +1,70 @@
+/*******************************************************************************
+ * Copyright (c) 2015 Luaj.org. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ ******************************************************************************/
+package org.luaj.vm2;
+
+import java.io.InputStream;
+import java.io.Reader;
+
+import junit.framework.TestCase;
+
+import org.luaj.vm2.lib.jse.JsePlatform;
+import org.luaj.vm2.server.Launcher;
+import org.luaj.vm2.server.LuajClassLoader;
+
+// Tests using class loading orders that have caused problems for some use cases.
+public class LoadOrderTest extends TestCase {
+
+	public void testLoadGlobalsFirst() {
+		Globals g = JsePlatform.standardGlobals();
+		assertNotNull(g);
+	}
+
+	public void testLoadStringFirst() {
+		LuaString BAR = LuaString.valueOf("bar");
+		assertNotNull(BAR);
+	}
+
+	public static class TestLauncherLoadStringFirst implements Launcher {
+		// Static initializer that causes LuaString->LuaValue->LuaString
+		private static final LuaString FOO = LuaString.valueOf("foo");
+
+		public Object[] launch(String script, Object[] arg) {
+			return new Object[] { FOO };
+		}
+
+		public Object[] launch(InputStream script, Object[] arg) {
+			return null;
+		}
+
+		public Object[] launch(Reader script, Object[] arg) {
+			return null;
+		}
+	}
+
+	public void testClassLoadsStringFirst() throws Exception {
+		Launcher launcher = LuajClassLoader
+				.NewLauncher(TestLauncherLoadStringFirst.class);
+		Object[] results = launcher.launch("foo", null);
+		assertNotNull(results);
+	}
+
+}