Unable to connect to Google Cloud SQL with eclipse

Question

I'm having trouble connecting to my database from eclipse. The mysql java connector & the mysql socket factory connector jar files are included in the build path. I'm not sure what is causing the NoClassDefFound error. The credentials are correct and omitted in the code.

My code:

import java.sql.*;

public class TestConnect {

private static String instanceConnectionName = "sampleInstanceName";
private static String databaseName = "sampleDatabaseName";
private static Connection connection = null;
private static String userName="sampleUserName";
private static String password="samplePassword";
private static String dbURL = String.format("jdbc:mysql://google/%s?cloudSqlInstance=%s&"
                                + "socketFactory=com.google.cloud.sql.mysql.SocketFactory",
                                databaseName, instanceConnectionName);

public static void main(String[] args) {
    // TODO Auto-generated method stub
            try {
                Class.forName("com.mysql.jdbc.Driver");
            } catch (Exception e) {
                System.out.println("Where is your MySQL JDBC Driver?");
                e.printStackTrace();
                return;
            }
            System.out.println("MySQL JDBC Driver Registered!");
            CreateConnection();
    }

    public static void CreateConnection() {
            try {
            // connect 
                connection = DriverManager.getConnection(dbURL,userName, password); 
            } catch (SQLException ex) {
                System.out.println("Connection Failed! Check output console");
                ex.printStackTrace();
            }
        }

}

Here is the pom.xml:

  <dependencies>
<!-- https://mvnrepository.com/artifact/com.google.cloud.sql/mysql-socket-factory -->
<dependency>
    <groupId>com.google.cloud.sql</groupId>
    <artifactId>mysql-socket-factory</artifactId>
    <version>1.0.4</version>
</dependency>
<dependency>                        <!-- http://dev.mysql.com/doc/connector-j/en/ -->
  <groupId>mysql</groupId>
  <artifactId>mysql-connector-java</artifactId>
  <version>5.1.44</version>
</dependency>

  </dependencies>
</project>

And here is the error message:

java.sql.SQLException: java.lang.NoClassDefFoundError: com/mysql/cj/api/io/SocketFactory
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:964)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:897)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:886)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:860)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:877)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:873)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:443)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:389)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:330)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at TestConnect.CreateConnection(TestConnect.java:32)
    at TestConnect.main(TestConnect.java:26)
Caused by: java.lang.NoClassDefFoundError: com/mysql/cj/api/io/SocketFactory
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(Unknown Source)
    at java.security.SecureClassLoader.defineClass(Unknown Source)
    at java.net.URLClassLoader.defineClass(Unknown Source)
    at java.net.URLClassLoader.access$100(Unknown Source)
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Unknown Source)
    at com.mysql.jdbc.MysqlIO.createSocketFactory(MysqlIO.java:3328)
    at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:296)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2189)
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2222)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2017)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:779)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
    ... 6 more
Caused by: java.lang.ClassNotFoundException: com.mysql.cj.api.io.SocketFactory
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    ... 32 more

UPDATE

I updated the jar files and removed the unnecessary ones and updated the pom file accordingly.

Here is the new pom file:

  <dependencies>
<!-- https://mvnrepository.com/artifact/com.google.cloud.sql/mysql-socket-factory-connector-j-6 -->
<dependency>
    <groupId>com.google.cloud.sql</groupId>
    <artifactId>mysql-socket-factory-connector-j-6</artifactId>
    <version>1.0.4</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.google.cloud.sql/jdbc-socket-factory-core -->
<dependency>
    <groupId>com.google.cloud.sql</groupId>
    <artifactId>jdbc-socket-factory-core</artifactId>
    <version>1.0.4</version>
</dependency>
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>6.0.6</version>
</dependency>   
  </dependencies>

And here is the new error message:

Exception in thread "main" java.lang.NoClassDefFoundError: com/google/common/base/Preconditions
    at com.google.cloud.sql.mysql.SocketFactory.connect(SocketFactory.java:41)
    at com.mysql.cj.mysqla.io.MysqlaSocketConnection.connect(MysqlaSocketConnection.java:57)
    at com.mysql.cj.mysqla.MysqlaSession.connect(MysqlaSession.java:122)
    at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:1726)
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:1596)
    at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:633)
    at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:347)
    at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:219)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at TestConnect.CreateConnection(TestConnect.java:30)
    at TestConnect.main(TestConnect.java:24)
Caused by: java.lang.ClassNotFoundException: com.google.common.base.Preconditions
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    ... 12 more

Answer 1

com.mysql.cj.api.io.SocketFactory is part of the MySQL Connector/J version 6. This is used by the SocketFactory in the mysql-socket-factory-connector-j-6. However the pom.xml you shared, uses mysql-socket-factory which is the version 5 packet and shouldn't use it.

Is it possible that you used mysql-socket-factory-connector-j-6 previously and it is in your libraries from that? This could allow the v6 SocketFactory to be loaded by mistake, causing this issue. If so try mvn clean to get rid of the old jar file and try running again.