From 2fbb3b00c72d36e65a459de98cba42836df5ee17 Mon Sep 17 00:00:00 2001
From: Jens Schauder <jschauder@pivotal.io>
Date: Wed, 25 Oct 2017 14:57:55 +0200
Subject: [PATCH] DATAJDBC-136 - Fix ClassNotFoundException when MyBatis is not
 on the classpath.

---
 .../support/JdbcRepositoryFactoryBean.java    | 16 +++++++++---
 .../JdbcRepositoryFactoryBeanUnitTests.java   | 25 +++++++++++++++++++
 2 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/src/main/java/org/springframework/data/jdbc/repository/support/JdbcRepositoryFactoryBean.java b/src/main/java/org/springframework/data/jdbc/repository/support/JdbcRepositoryFactoryBean.java
index 1156e8206..942efe12a 100644
--- a/src/main/java/org/springframework/data/jdbc/repository/support/JdbcRepositoryFactoryBean.java
+++ b/src/main/java/org/springframework/data/jdbc/repository/support/JdbcRepositoryFactoryBean.java
@@ -118,12 +118,22 @@ public class JdbcRepositoryFactoryBean<T extends Repository<S, ID>, S, ID extend
 
 	private Optional<DataAccessStrategy> createMyBatisDataAccessStrategy() {
 
-		if (!ClassUtils.isPresent("org.apache.ibatis.session.SqlSessionFactory", this.getClass().getClassLoader())) {
+		String myBatisSqlSessionFactoryClassName = "org.apache.ibatis.session.SqlSessionFactory";
+		ClassLoader classLoader = this.getClass().getClassLoader();
+
+		if (!ClassUtils.isPresent(myBatisSqlSessionFactoryClassName, classLoader)) {
 			return Optional.empty();
 		}
 
-		return getBean(SqlSessionFactory.class, SQL_SESSION_FACTORY_BEAN_NAME)
-				.map(ssf -> new MyBatisDataAccessStrategy(ssf));
+		try {
+			
+			return getBean(classLoader.loadClass(myBatisSqlSessionFactoryClassName), SQL_SESSION_FACTORY_BEAN_NAME)
+					// note that the cast to SqlSessionFactory happens in a lambda, which is basically a separate class
+					// thus it won't get loaded if this code path doesn't get executed.
+					.map(ssf -> new MyBatisDataAccessStrategy((SqlSessionFactory) ssf));
+		} catch (ClassNotFoundException e) {
+			throw new IllegalStateException("Detected MyBatis on classpath but failed to load the class " + myBatisSqlSessionFactoryClassName);
+		}
 	}
 
 	private Optional<DataAccessStrategy> createDefaultAccessStrategy(JdbcMappingContext context,
diff --git a/src/test/java/org/springframework/data/jdbc/repository/support/JdbcRepositoryFactoryBeanUnitTests.java b/src/test/java/org/springframework/data/jdbc/repository/support/JdbcRepositoryFactoryBeanUnitTests.java
index 0cca7ab3a..513d9231d 100644
--- a/src/test/java/org/springframework/data/jdbc/repository/support/JdbcRepositoryFactoryBeanUnitTests.java
+++ b/src/test/java/org/springframework/data/jdbc/repository/support/JdbcRepositoryFactoryBeanUnitTests.java
@@ -25,9 +25,11 @@ import org.springframework.data.jdbc.core.DelegatingDataAccessStrategy;
 import org.springframework.data.jdbc.mybatis.MyBatisDataAccessStrategy;
 import org.springframework.data.repository.CrudRepository;
 import org.springframework.data.repository.core.support.RepositoryFactorySupport;
+import org.springframework.instrument.classloading.ShadowingClassLoader;
 import org.springframework.jdbc.core.JdbcOperations;
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.jdbc.core.namedparam.NamedParameterJdbcOperations;
+import org.springframework.util.ReflectionUtils;
 
 /**
  * Tests the dependency injection for {@link JdbcRepositoryFactoryBean}.
@@ -211,6 +213,29 @@ public class JdbcRepositoryFactoryBeanUnitTests {
 		assertThat(findDataAccessStrategy(factory, MyBatisDataAccessStrategy.class)).isNotNull();
 	}
 
+	@Test // DATAJDBC-136
+	public void canBeLoadedWithoutMyBatis() throws Exception {
+
+		String sqlSessionFactoryClassName = SqlSessionFactory.class.getName();
+
+		ShadowingClassLoader classLoader = new ShadowingClassLoader(this.getClass().getClassLoader()) {
+
+			@Override
+			public Class<?> loadClass(String name) throws ClassNotFoundException {
+
+				if (name.equals(sqlSessionFactoryClassName)) {
+					throw new ClassNotFoundException("%s is configured not to get loaded by this classloader");
+				}
+				return super.loadClass(name);
+			}
+		};
+
+		Class<?> loadedClass = classLoader.loadClass(JdbcRepositoryFactoryBean.class.getName());
+
+		assertThat(loadedClass).isNotNull();
+		ReflectionUtils.getAllDeclaredMethods(loadedClass);
+	}
+
 	private Condition<? super RepositoryFactorySupport> using(NamedParameterJdbcOperations expectedOperations) {
 
 		Predicate<RepositoryFactorySupport> predicate = r -> extractNamedParameterJdbcOperations(r) == expectedOperations;