CloudSQL Eclipse Java Standard GAE java.lang.UnsatisfiedLinkError - google-app-engine

Question

I am building a simple Java Standard Google App Engine application that connects to a Google CloudSQL instance. When I execute the project from command line using mvn clean appengine:run or mvn clean appengine:deploy, I could successfully connect to the database in the CloudSQL instance.
However, if I run or debug the project from Eclipse "Run as"-> App Engine or "Debug as" -> App Engine feature, I receive the following error when DriverManager.getConnection(serverURL) is executed.
INFO: Dev App Server is now running
connecting to: REDACTED
Jun 05, 2018 10:06:06 AM com.google.cloud.sql.mysql.SocketFactory connect
INFO: Connecting to Cloud SQL instance [REDACTED].
Jun 05, 2018 10:06:06 AM com.google.cloud.sql.mysql.SocketFactory connect
INFO: Using GAE Unix Sockets
java.sql.SQLException: java.lang.UnsatisfiedLinkError: The operation
completed successfully.
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 generic.HelloAppEngine.init(HelloAppEngine.java:55)
at javax.servlet.GenericServlet.init(GenericServlet.java:244)
at org.eclipse.jetty.servlet.ServletHolder.initServlet(ServletHolder.java:643)
at org.eclipse.jetty.servlet.ServletHolder.getServlet(ServletHolder.java:499)
at org.eclipse.jetty.servlet.ServletHolder.ensureInstance(ServletHolder.java:791)
at org.eclipse.jetty.servlet.ServletHolder.prepare(ServletHolder.java:776)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:579)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:524)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:226)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1180)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:512)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1112)
at com.google.appengine.tools.development.jetty9.DevAppEngineWebAppContext.doScope(DevAppEngineWebAppContext.java:94)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:134)
at com.google.appengine.tools.development.jetty9.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:597)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:134)
at org.eclipse.jetty.server.Server.handle(Server.java:534)
at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:320)
at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:251)
at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:283)
at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:108)
at org.eclipse.jetty.io.SelectChannelEndPoint$2.run(SelectChannelEndPoint.java:93)
at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.executeProduceConsume(ExecuteProduceConsume.java:303)
at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.produceConsume(ExecuteProduceConsume.java:148)
at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.run(ExecuteProduceConsume.java:136)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:671)
at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:589)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.UnsatisfiedLinkError: The operation completed successfully.
at jnr.ffi.provider.jffi.AsmRuntime.newUnsatisifiedLinkError(AsmRuntime.java:40)
at jnr.unixsocket.Native$LibC$jnr$ffi$0.socket(Unknown Source)
at jnr.unixsocket.Native.socket(Native.java:92)
at jnr.unixsocket.UnixSocketChannel.<init>(UnixSocketChannel.java:101)
at jnr.unixsocket.UnixSocketChannel.open(UnixSocketChannel.java:65)
at com.google.cloud.sql.mysql.SocketFactory.connect(SocketFactory.java:61)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:300)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2192)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2225)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2024)
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)
... 35 more
My POM.xml is
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<packaging>war</packaging>
<version>0.1.0-SNAPSHOT</version>
<groupId>generic</groupId>
<artifactId>testdb</artifactId>
<properties>
<appengine.api.sdk.version>1.9.63</appengine.api.sdk.version>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
<maven.compiler.showDeprecation>true</maven.compiler.showDeprecation>
</properties>
<dependencies>
<dependency>
<groupId>com.google.cloud</groupId>
<artifactId>google-cloud-bom</artifactId>
<version>0.47.0-alpha</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<!-- Compile/runtime dependencies -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>javax.servlet.jsp-api</artifactId>
<version>2.3.1</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>jstl</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<dependency> <!-- Only used locally -->
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.42</version>
</dependency>
<dependency>
<groupId>com.google.cloud.sql</groupId>
<artifactId>mysql-socket-factory</artifactId>
<version>1.0.8</version>
</dependency>
<!-- Test Dependencies -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<!-- for hot reload of the web application -->
<outputDirectory>${project.build.directory}/${project.build.finalName}/WEB-INF/classes</outputDirectory>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>3.0.0</version>
<configuration>
<webResources>
<!-- in order to interpolate version from pom into appengine-web.xml -->
<resource>
<directory>${basedir}/src/main/webapp/WEB-INF</directory>
<filtering>true</filtering>
<targetPath>WEB-INF</targetPath>
</resource>
</webResources>
</configuration>
</plugin>
<plugin>
<groupId>com.google.cloud.tools</groupId>
<artifactId>appengine-maven-plugin</artifactId>
<version>1.3.1</version>
</plugin>
</plugins>
</build>
</project>
My Servlet is:
package generic;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.google.common.base.Stopwatch;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Timestamp;
import java.util.Date;
import java.util.concurrent.TimeUnit;
#SuppressWarnings("serial")
#WebServlet(
name = "HelloAppEngine",
urlPatterns = {"/hello"}
)
public class HelloAppEngine extends HttpServlet {
Connection conn;
#Override
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws IOException {
resp.setContentType("text/plain");
resp.setCharacterEncoding("UTF-8");
resp.getWriter().print("Hello App Engine!\r\n");
if(conn!=null)
resp.getWriter().println("connected:"+conn.toString());
}
#Override
public void init()
{
//String url = System.getProperty("cloudsql");
String serverURL = "jdbc:mysql://google/DB?cloudSqlInstance=INSTANCE&"+ "socketFactory=com.google.cloud.sql.mysql.SocketFactory&user=USER&password=PWD&useSSL=false";
//System.out.println("connecting to: " + url);
System.out.println("connecting to: " + serverURL);
try {
conn = DriverManager.getConnection(serverURL);
} catch (SQLException e) {
e.printStackTrace();
}
}
}
My appengine-web.xml is:
<?xml version="1.0" encoding="utf-8"?>
<appengine-web-app xmlns="http://appengine.google.com/ns/1.0">
<threadsafe>true</threadsafe>
<runtime>java8</runtime>
</appengine-web-app>
Please help me run and debug this app in Eclipse!!

Answer 1

UPDATE: the issue has been fixed. Upgrade to the latest Cloud SQL JDBC socket library.
There is an issue in the Cloud SQL JDBC socket factory library; it is incorrectly assuming the code is running on App Engine servers: https://github.com/GoogleCloudPlatform/cloud-sql-jdbc-socket-factory/issues/77. They are working on a fix (as noted in the GitHub issue), and unfortunately, there does not seem an immediate workaround as long as you use the socket factory library.
The reason that mvn appengine:run worked was that you were using an old version (1.3.1) of the com.google.cloud.tools:appengine-maven-plugin plugin. Upgrading it to 1.3.2 will break things as it currently does with the Eclipse plugin (the Cloud Tools for Eclipse plugin).
Technical Details
For those who are interested in the technical details of the root cause, refer to the GitHub issue above and the following: https://github.com/GoogleCloudPlatform/google-cloud-eclipse/issues/3136. Basically, recent versions of the plugins make GAE_RUNTIME and GAE_ENV environment variables available on the local App Engine development server, which made the JDBC socket library to incorrectly assume that it is on a production server.