Demonstrating the issue reported in mybatis#902 .

pom.xml

@@ -245,6 +245,12 @@
       <version>9.1-901-1.jdbc4</version>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>ru.yandex.qatools.embed</groupId>
+      <artifactId>postgresql-embedded</artifactId>
+      <version>2.2</version>
+      <scope>test</scope>
+    </dependency>
     <dependency>
       <groupId>org.assertj</groupId>
       <artifactId>assertj-core</artifactId>

src/test/java/org/apache/ibatis/submitted/usesjava8/postgres_genkeys/CreateDB.sql

@@ -0,0 +1,34 @@
+--
+--    Copyright 2009-2017 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.
+--
+
+CREATE SCHEMA mbtest;
+
+CREATE TABLE mbtest.users (
+  user_id serial PRIMARY KEY,
+  name character varying(30)
+);
+
+INSERT INTO mbtest.users (name) values 
+('Jimmy');
+
+
+CREATE TABLE mbtest.sections (
+  section_id int PRIMARY KEY,
+  name character varying(30)
+);
+
+INSERT INTO mbtest.sections (section_id, name) values 
+(1, 'Section 1');

src/test/java/org/apache/ibatis/submitted/usesjava8/postgres_genkeys/Mapper.java

@@ -0,0 +1,27 @@
+/**
+ *    Copyright 2009-2017 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.apache.ibatis.submitted.usesjava8.postgres_genkeys;
+
+import org.apache.ibatis.annotations.Param;
+import org.apache.ibatis.annotations.Update;
+
+public interface Mapper {
+  @Update("update mbtest.users set name = #{name} where user_id = #{userId}")
+  int updateUserById(@Param("userId") Integer userId, @Param("name") String name);
+
+  @Update("update mbtest.sections set name = #{name} where section_id = #{sectionId}")
+  int updateSectionById(@Param("sectionId") Integer sectionId, @Param("name") String name);
+}

src/test/java/org/apache/ibatis/submitted/usesjava8/postgres_genkeys/MapperConfig.xml

@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<!--
+
+       Copyright 2009-2017 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.
+
+-->
+<!DOCTYPE configuration
+    PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
+    "http://mybatis.org/dtd/mybatis-3-config.dtd">
+<configuration>
+  <settings>
+    <setting name="useGeneratedKeys" value="true" />
+  </settings>
+  <environments default="development">
+    <environment id="development">
+      <transactionManager type="JDBC">
+        <property name="" value="" />
+      </transactionManager>
+      <dataSource type="UNPOOLED">
+        <property name="driver" value="org.postgresql.Driver" />
+        <property name="url" value="jdbc:postgresql:postgres_genkeys" />
+        <property name="username" value="postgres" />
+        <property name="password" value="root" />
+      </dataSource>
+    </environment>
+  </environments>
+  <mappers>
+    <mapper
+      class="org.apache.ibatis.submitted.usesjava8.postgres_genkeys.Mapper" />
+  </mappers>
+</configuration>

src/test/java/org/apache/ibatis/submitted/usesjava8/postgres_genkeys/PostgresGeneratedKeysTest.java

@@ -0,0 +1,89 @@
+/**
+ *    Copyright 2009-2017 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.apache.ibatis.submitted.usesjava8.postgres_genkeys;
+
+import static org.junit.Assert.*;
+
+import java.io.Reader;
+import java.nio.file.Paths;
+import java.sql.Connection;
+import java.util.Collections;
+
+import org.apache.ibatis.io.Resources;
+import org.apache.ibatis.jdbc.ScriptRunner;
+import org.apache.ibatis.session.SqlSession;
+import org.apache.ibatis.session.SqlSessionFactory;
+import org.apache.ibatis.session.SqlSessionFactoryBuilder;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import ru.yandex.qatools.embed.postgresql.EmbeddedPostgres;
+
+public class PostgresGeneratedKeysTest {
+
+  private static final EmbeddedPostgres postgres = new EmbeddedPostgres();
+
+  private static SqlSessionFactory sqlSessionFactory;
+
+  @BeforeClass
+  public static void setUp() throws Exception {
+    //  Launch PostgreSQL server. Download / unarchive if necessary.
+    postgres.start(EmbeddedPostgres.cachedRuntimeConfig(Paths.get("target/postgres")), "localhost", 5432, "postgres_genkeys", "postgres", "root", Collections.emptyList());
+
+    Reader reader = Resources.getResourceAsReader("org/apache/ibatis/submitted/usesjava8/postgres_genkeys/MapperConfig.xml");
+    sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
+    reader.close();
+
+    SqlSession session = sqlSessionFactory.openSession();
+    Connection conn = session.getConnection();
+    reader = Resources.getResourceAsReader("org/apache/ibatis/submitted/usesjava8/postgres_genkeys/CreateDB.sql");
+    ScriptRunner runner = new ScriptRunner(conn);
+    runner.setLogWriter(null);
+    runner.runScript(reader);
+    reader.close();
+    session.close();
+  }
+
+  @AfterClass
+  public static void tearDown() {
+    postgres.stop();
+  }
+
+  @Test
+  public void shouldDefaultKeyPropertyNotCauseException() throws Exception {
+    SqlSession sqlSession = sqlSessionFactory.openSession();
+    try {
+      Mapper mapper = sqlSession.getMapper(Mapper.class);
+      int result = mapper.updateUserById(1, "Ethan");
+      assertEquals(1, result);
+    } finally {
+      sqlSession.close();
+    }
+  }
+
+  @Test
+  public void shouldDefaultKeyPropertyNotCauseException2() throws Exception {
+    SqlSession sqlSession = sqlSessionFactory.openSession();
+    try {
+      Mapper mapper = sqlSession.getMapper(Mapper.class);
+      int result = mapper.updateSectionById(1, "IMF");
+      assertEquals(1, result);
+    } finally {
+      sqlSession.close();
+    }
+  }
+}

src/test/java/org/apache/ibatis/submitted/usesjava8/postgres_genkeys/User.java

@@ -0,0 +1,38 @@
+/**
+ *    Copyright 2009-2017 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.apache.ibatis.submitted.usesjava8.postgres_genkeys;
+
+public class User {
+  private Integer id;
+
+  private String name;
+
+  public Integer getId() {
+    return id;
+  }
+
+  public void setId(Integer id) {
+    this.id = id;
+  }
+
+  public String getName() {
+    return name;
+  }
+
+  public void setName(String name) {
+    this.name = name;
+  }
+}