Change the default JDBC connection pool to Hikari

Closes gh-6013

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/autoconfigure/PublicMetricsAutoConfigurationTests.java

@@ -126,9 +126,10 @@ public class PublicMetricsAutoConfigurationTests {
 	}
 
 	@Test
-	public void autoDataSource() {
+	public void autoDataSource() throws SQLException {
 		load(DataSourceAutoConfiguration.class);
 		PublicMetrics bean = this.context.getBean(DataSourcePublicMetrics.class);
+		this.context.getBean(DataSource.class).getConnection().close();
 		Collection<Metric<?>> metrics = bean.metrics();
 		assertMetrics(metrics, "datasource.primary.active", "datasource.primary.usage");
 	}

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/jdbc/DataSourceAutoConfiguration.java

@@ -104,7 +104,7 @@ public class DataSourceAutoConfiguration {
 	@Configuration
 	@Conditional(PooledDataSourceCondition.class)
 	@ConditionalOnMissingBean({ DataSource.class, XADataSource.class })
-	@Import({ DataSourceConfiguration.Tomcat.class, DataSourceConfiguration.Hikari.class,
+	@Import({ DataSourceConfiguration.Hikari.class, DataSourceConfiguration.Tomcat.class,
 			DataSourceConfiguration.Dbcp2.class, DataSourceConfiguration.Generic.class })
 	protected static class PooledDataSourceConfiguration {
 

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/jdbc/DataSourceAutoConfigurationTests.java

@@ -84,9 +84,8 @@ public class DataSourceAutoConfigurationTests {
 		this.context.register(DataSourceAutoConfiguration.class,
 				PropertyPlaceholderAutoConfiguration.class);
 		this.context.refresh();
-		org.apache.tomcat.jdbc.pool.DataSource dataSource = this.context
-				.getBean(org.apache.tomcat.jdbc.pool.DataSource.class);
-		assertThat(dataSource.getUrl()).isNotNull();
+		HikariDataSource dataSource = this.context.getBean(HikariDataSource.class);
+		assertThat(dataSource.getJdbcUrl()).isNotNull();
 		assertThat(dataSource.getDriverClassName()).isNotNull();
 	}
 
@@ -114,41 +113,41 @@ public class DataSourceAutoConfigurationTests {
 	}
 
 	@Test
-	public void tomcatValidatesConnectionByDefault() {
-		org.apache.tomcat.jdbc.pool.DataSource dataSource = autoConfigureDataSource(
-				org.apache.tomcat.jdbc.pool.DataSource.class);
-		assertThat(dataSource.isTestOnBorrow()).isTrue();
-		assertThat(dataSource.getValidationQuery())
-				.isEqualTo(DatabaseDriver.HSQLDB.getValidationQuery());
+	public void hikariValidatesConnectionByDefault() throws Exception {
+		HikariDataSource dataSource = autoConfigureDataSource(HikariDataSource.class,
+				"org.apache.tomcat");
+		assertThat(dataSource.getConnectionTestQuery()).isNull();
+		// Use Connection#isValid()
 	}
 
 	@Test
-	public void hikariIsFallback() throws Exception {
-		HikariDataSource dataSource = autoConfigureDataSource(HikariDataSource.class,
-				"org.apache.tomcat");
-		assertThat(dataSource.getJdbcUrl()).isEqualTo("jdbc:hsqldb:mem:testdb");
+	public void tomcatIsFallback() throws Exception {
+		org.apache.tomcat.jdbc.pool.DataSource dataSource = autoConfigureDataSource(
+				org.apache.tomcat.jdbc.pool.DataSource.class, "com.zaxxer.hikari");
+		assertThat(dataSource.getUrl()).isEqualTo("jdbc:hsqldb:mem:testdb");
 	}
 
 	@Test
-	public void hikariValidatesConnectionByDefault() throws Exception {
-		HikariDataSource dataSource = autoConfigureDataSource(HikariDataSource.class,
-				"org.apache.tomcat");
-		assertThat(dataSource.getConnectionTestQuery()).isNull();
-		// Use Connection#isValid()
+	public void tomcatValidatesConnectionByDefault() {
+		org.apache.tomcat.jdbc.pool.DataSource dataSource = autoConfigureDataSource(
+				org.apache.tomcat.jdbc.pool.DataSource.class, "com.zaxxer.hikari");
+		assertThat(dataSource.isTestOnBorrow()).isTrue();
+		assertThat(dataSource.getValidationQuery())
+				.isEqualTo(DatabaseDriver.HSQLDB.getValidationQuery());
 	}
 
 	@Test
 	public void commonsDbcp2IsFallback() throws Exception {
 		BasicDataSource dataSource = autoConfigureDataSource(BasicDataSource.class,
-				"org.apache.tomcat", "com.zaxxer.hikari");
+				"com.zaxxer.hikari", "org.apache.tomcat");
 		assertThat(dataSource.getUrl()).isEqualTo("jdbc:hsqldb:mem:testdb");
 	}
 
 	@Test
 	public void commonsDbcp2ValidatesConnectionByDefault() throws Exception {
 		org.apache.commons.dbcp2.BasicDataSource dataSource = autoConfigureDataSource(
-				org.apache.commons.dbcp2.BasicDataSource.class, "org.apache.tomcat",
-				"com.zaxxer.hikari");
+				org.apache.commons.dbcp2.BasicDataSource.class, "com.zaxxer.hikari",
+				"org.apache.tomcat");
 		assertThat(dataSource.getTestOnBorrow()).isEqualTo(true);
 		assertThat(dataSource.getValidationQuery()).isNull(); // Use Connection#isValid()
 	}
@@ -163,7 +162,7 @@ public class DataSourceAutoConfigurationTests {
 		this.context.refresh();
 		DataSource bean = this.context.getBean(DataSource.class);
 		assertThat(bean).isNotNull();
-		org.apache.tomcat.jdbc.pool.DataSource pool = (org.apache.tomcat.jdbc.pool.DataSource) bean;
+		HikariDataSource pool = (HikariDataSource) bean;
 		assertThat(pool.getDriverClassName()).isEqualTo("org.hsqldb.jdbcDriver");
 		assertThat(pool.getUsername()).isEqualTo("sa");
 	}
@@ -215,7 +214,7 @@ public class DataSourceAutoConfigurationTests {
 		this.context.refresh();
 		DataSource bean = this.context.getBean(DataSource.class);
 		assertThat(bean).isNotNull();
-		org.apache.tomcat.jdbc.pool.DataSource pool = (org.apache.tomcat.jdbc.pool.DataSource) bean;
+		HikariDataSource pool = (HikariDataSource) bean;
 		assertThat(pool.getDriverClassName()).isEqualTo(
 				"org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfigurationTests$DatabaseTestDriver");
 		assertThat(pool.getUsername()).isNull();

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/jdbc/DataSourceInitializerTests.java

@@ -24,6 +24,7 @@ import java.util.Random;
 
 import javax.sql.DataSource;
 
+import com.zaxxer.hikari.HikariDataSource;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Rule;
@@ -112,7 +113,7 @@ public class DataSourceInitializerTests {
 				PropertyPlaceholderAutoConfiguration.class);
 		this.context.refresh();
 		DataSource dataSource = this.context.getBean(DataSource.class);
-		assertThat(dataSource instanceof org.apache.tomcat.jdbc.pool.DataSource).isTrue();
+		assertThat(dataSource).isInstanceOf(HikariDataSource.class);
 		assertThat(dataSource).isNotNull();
 		JdbcOperations template = new JdbcTemplate(dataSource);
 		assertThat(template.queryForObject("SELECT COUNT(*) from BAR", Integer.class))
@@ -131,7 +132,7 @@ public class DataSourceInitializerTests {
 						.addResourcePathToPackagePath(getClass(), "data.sql"));
 		this.context.refresh();
 		DataSource dataSource = this.context.getBean(DataSource.class);
-		assertThat(dataSource instanceof org.apache.tomcat.jdbc.pool.DataSource).isTrue();
+		assertThat(dataSource).isInstanceOf(HikariDataSource.class);
 		assertThat(dataSource).isNotNull();
 		JdbcOperations template = new JdbcTemplate(dataSource);
 		assertThat(template.queryForObject("SELECT COUNT(*) from FOO", Integer.class))
@@ -154,7 +155,7 @@ public class DataSourceInitializerTests {
 				PropertyPlaceholderAutoConfiguration.class);
 		this.context.refresh();
 		DataSource dataSource = this.context.getBean(DataSource.class);
-		assertThat(dataSource instanceof org.apache.tomcat.jdbc.pool.DataSource).isTrue();
+		assertThat(dataSource).isInstanceOf(HikariDataSource.class);
 		assertThat(dataSource).isNotNull();
 		JdbcOperations template = new JdbcTemplate(dataSource);
 		assertThat(template.queryForObject("SELECT COUNT(*) from FOO", Integer.class))
@@ -177,7 +178,7 @@ public class DataSourceInitializerTests {
 						.addResourcePathToPackagePath(getClass(), "encoding-data.sql"));
 		this.context.refresh();
 		DataSource dataSource = this.context.getBean(DataSource.class);
-		assertThat(dataSource instanceof org.apache.tomcat.jdbc.pool.DataSource).isTrue();
+		assertThat(dataSource).isInstanceOf(HikariDataSource.class);
 		assertThat(dataSource).isNotNull();
 		JdbcOperations template = new JdbcTemplate(dataSource);
 		assertThat(template.queryForObject("SELECT COUNT(*) from BAR", Integer.class))
@@ -197,7 +198,7 @@ public class DataSourceInitializerTests {
 		this.context.refresh();
 		DataSource dataSource = this.context.getBean(DataSource.class);
 		this.context.publishEvent(new DataSourceInitializedEvent(dataSource));
-		assertThat(dataSource instanceof org.apache.tomcat.jdbc.pool.DataSource).isTrue();
+		assertThat(dataSource).isInstanceOf(HikariDataSource.class);
 		assertThat(dataSource).isNotNull();
 		JdbcOperations template = new JdbcTemplate(dataSource);
 		try {
@@ -270,7 +271,7 @@ public class DataSourceInitializerTests {
 		this.context.setResourceLoader(resourceLoader);
 		this.context.refresh();
 		DataSource dataSource = this.context.getBean(DataSource.class);
-		assertThat(dataSource instanceof org.apache.tomcat.jdbc.pool.DataSource).isTrue();
+		assertThat(dataSource).isInstanceOf(HikariDataSource.class);
 		assertThat(dataSource).isNotNull();
 		JdbcOperations template = new JdbcTemplate(dataSource);
 		assertThat(template.queryForObject("SELECT COUNT(*) from FOO", Integer.class))

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/orm/jpa/CustomHibernateJpaAutoConfigurationTests.java

@@ -64,6 +64,7 @@ public class CustomHibernateJpaAutoConfigurationTests {
 		// Set up environment so we get a MySQL database but don't require server to be
 		// running...
 		EnvironmentTestUtils.addEnvironment(this.context,
+				"spring.datasource.type:" + org.apache.tomcat.jdbc.pool.DataSource.class.getName(),
 				"spring.datasource.database:mysql",
 				"spring.datasource.url:jdbc:mysql://localhost/nonexistent",
 				"spring.datasource.initialize:false", "spring.jpa.database:MYSQL");

spring-boot-docs/src/main/asciidoc/spring-boot-features.adoc

@@ -2821,10 +2821,10 @@ ensuring that it happens once access to the database is no longer needed.
 Production database connections can also be auto-configured using a pooling `DataSource`.
 Here's the algorithm for choosing a specific implementation:
 
-* We prefer the Tomcat pooling `DataSource` for its performance and concurrency, so if
-  that is available we always choose it.
-* Otherwise, if HikariCP is available we will use it.
-* If neither the Tomcat pooling datasource nor HikariCP are available and if Commons
+* We prefer HikariCP for its performance and concurrency, so if that is available we
+  always choose it.
+* Otherwise, if the Tomcat pooling `DataSource` is available we will use it.
+* If neither HikariCP nor the Tomcat pooling datasource are available and if Commons
   DBCP2 is available we will use it.
 
 If you use the `spring-boot-starter-jdbc` or `spring-boot-starter-data-jpa`
@@ -2863,8 +2863,8 @@ loadable.
 See {sc-spring-boot-autoconfigure}/jdbc/DataSourceProperties.{sc-ext}[`DataSourceProperties`]
 for more of the supported options. These are the standard options that work regardless of
 the actual implementation. It is also possible to fine-tune implementation-specific
-settings using their respective prefix (`+spring.datasource.tomcat.*+`,
-`+spring.datasource.hikari.*+`, and `+spring.datasource.dbcp2.*+`). Refer to the
+settings using their respective prefix (`+spring.datasource.hikari.*+`,
+`+spring.datasource.tomcat.*+`, and `+spring.datasource.dbcp2.*+`). Refer to the
 documentation of the connection pool implementation you are using for more details.
 
 For instance, if you are using the