Allow package private classes in spring.factories

Update SpringFactoriesLoader so that package private classes can be
used.

Issue: SPR-13969

spring-core/src/main/java/org/springframework/core/io/support/SpringFactoriesLoader.java

 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,6 +17,7 @@
 package org.springframework.core.io.support;
 
 import java.io.IOException;
+import java.lang.reflect.Constructor;
 import java.net.URL;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -31,6 +32,7 @@ import org.springframework.core.annotation.AnnotationAwareOrderComparator;
 import org.springframework.core.io.UrlResource;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
+import org.springframework.util.ReflectionUtils;
 import org.springframework.util.StringUtils;
 
 /**
@@ -132,7 +134,9 @@ public abstract class SpringFactoriesLoader {
 				throw new IllegalArgumentException(
 						"Class [" + instanceClassName + "] is not assignable to [" + factoryClass.getName() + "]");
 			}
-			return (T) instanceClass.newInstance();
+			Constructor<?> constructor = instanceClass.getDeclaredConstructor();
+			ReflectionUtils.makeAccessible(constructor);
+			return (T) constructor.newInstance();
 		}
 		catch (Throwable ex) {
 			throw new IllegalArgumentException("Cannot instantiate factory class: " + factoryClass.getName(), ex);

spring-core/src/test/java/org/springframework/core/io/support/DummyPackagePrivateFactory.java

+/*
+ * Copyright 2002-2016 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.core.io.support;
+
+/**
+ * Used by {@link SpringFactoriesLoaderTests}
+
+ * @author Phillip Webb
+ */
+class DummyPackagePrivateFactory {
+
+}

spring-core/src/test/java/org/springframework/core/io/support/SpringFactoriesLoaderTests.java

+/*
+ * Copyright 2002-2016 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.core.io.support;
+
+import java.lang.reflect.Modifier;
+import java.util.List;
+
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+/**
+ * Tests for {@link SpringFactoriesLoader}.
+ *
+ * @author Arjen Poutsma
+ * @author Phillip Webb
+ */
+public class SpringFactoriesLoaderTests {
+
+	@Test
+	public void loadFactoriesInCorrectOrder() {
+		List<DummyFactory> factories = SpringFactoriesLoader
+				.loadFactories(DummyFactory.class, null);
+		assertEquals(2, factories.size());
+		assertTrue(factories.get(0) instanceof MyDummyFactory1);
+		assertTrue(factories.get(1) instanceof MyDummyFactory2);
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void loadInvalid() {
+		SpringFactoriesLoader.loadFactories(String.class, null);
+	}
+
+	@Test
+	public void loadPackagePrivateFactory() throws Exception {
+		List<DummyPackagePrivateFactory> factories = SpringFactoriesLoader
+				.loadFactories(DummyPackagePrivateFactory.class, null);
+		assertEquals(1, factories.size());
+		assertTrue((factories.get(0).getClass().getModifiers() & Modifier.PUBLIC) == 0);
+	}
+
+}

spring-core/src/test/resources/META-INF/spring.factories

+org.springframework.core.io.support.DummyFactory=\
+org.springframework.core.io.support.MyDummyFactory2,\
+org.springframework.core.io.support.MyDummyFactory1
+
+java.lang.String=\
+org.springframework.core.io.support.MyDummyFactory1
+
+org.springframework.core.io.support.DummyPackagePrivateFactory=\
+org.springframework.core.io.support.DummyPackagePrivateFactory

spring-core/src/test/resources/org/springframework/core/io/support/springFactoriesLoaderTests.properties

-org.springframework.core.io.support.DummyFactory=org.springframework.core.io.support.MyDummyFactory2,org.springframework.core.io.support.MyDummyFactory1
-java.lang.String=org.springframework.core.io.support.MyDummyFactory1
\ No newline at end of file