Using JDBC connector to connect to mapR drill failing without any Exception

I am building a java app that gets data from the file system (parquet) in mapR cluster. I was initially using apache spark but the processing was quite slow.
So i decided to use the drill jdbc connection approach.

Following the documentation in mapR https://mapr.com/docs/52/Drill/Using-JDBC-Driver-App.html

Here is my code

Step 1;
placed the driver jar in a lib folder in my project path as shown;

[project directory][1]
  [1]: https://i.stack.imgur.com/APsZi.png

step 2; 
Imported the jar to my maven pom.xml
        <dependency>
            <groupId>DrillJDBC41</groupId>
            <artifactId>DrillJDBC41</artifactId>
            <scope>system</scope>
            <version>1.0</version>
            <systemPath>${project.basedir}\src\lib\DrillJDBC41.jar</systemPath>
        </dependency>

step 3
my code implementation
       

        try {


 private static final String CONNECTION_URL = "jdbc:drill:zk=192.168.1.1:31010/drill/dev.maprcluster.com-drillbits;schema=dfs";



 private static final String JDBC_DRIVER = "com.mapr.drill.jdbc41.Driver";

 Connection con = null;
        Statement stmt = null;
        ResultSet rs = null;
        // Define a plain query
        String query = "SELECT * FROM `dfs.default`.`/storage/products/data/d/report/2019/07/12`" + " where unique_key = '00209220' LIMIT 30";
       
            // Register the driver using the class name
            Class.forName(JDBC_DRIVER);
            // Establish a connection using the connection
            // URL

            try {
                System.out.println("about establishing connection");
                con = DriverManager.getConnection(CONNECTION_URL);
                System.out.println("connection established");
            }catch (Exception e){
                System.out.println("EXCEPTION OO");
                e.printStackTrace();
            }
            // Create a Statement object for sending SQL
            // statements to the database
            stmt = con.createStatement();

            System.out.println("trying to execute query");
            // Execute the SQL statement
            rs = stmt.executeQuery(query);
            // Display a header line for output appearing in
            // the Console View
            System.out.println("gotten result set");

                    // Step through each row in the result set
                    // returned from the database
            while(rs.next()) {
                // Retrieve values from the row where the
                System.out.println("data is returned");
                // cursor is currently positioned using
                // column names

                // Display values in columns 20 characters
                // wide in the Console View using the
                // Formatter

            }
        } catch (SQLException se) {
            System.out.println("sql exception");
            se.printStackTrace();
            // Handle errors encountered during interaction
            // with the data source
        } catch (Exception e) {
            e.printStackTrace();
            // Handle other errors
        } finally {
            // Perform clean up
            try {
                System.out.println("entered finally block");
                if (rs != null) {
                    rs.close();
                }
                if (stmt != null) {
                    stmt.close();
                }
                if (con != null) {
                    con.close();
                }
            } catch (SQLException se1) {
                se1.printStackTrace();
            }
        } // End try
    }

PROBLEM

The application builds fine but when i try to get data , it stops after printing this;

about establishing connection

and goes straight into the finally block without throwing any exception.

I am not sure what the problem is.

I also tried another another implementation using apache drill

  <dependency>
            <groupId>org.apache.drill.exec</groupId>
            <artifactId>drill-jdbc-all</artifactId>
            <version>1.1.0</version>
</dependency>

changed the driver to this;

 private static final String JDBC_DRIVER_DRILL = "org.apache.drill.jdbc.Driver";

still the same problem.

No error thrown.

Output;

about establishing connection

entered finally block

UPDATE

I caught Throwable as advised and i was getting the following error;

java.lang.NoSuchMethodError: com.google.common.base.Stopwatch.createStarted()Lcom/google/common/base/Stopwatch;
	at org.apache.drill.common.config.DrillConfig.create(DrillConfig.java:189)
	at org.apache.drill.common.config.DrillConfig.create(DrillConfig.java:163)
	at org.apache.drill.common.config.DrillConfig.forClient(DrillConfig.java:114)
	at com.mapr.drill.drill.client.DRJDBCClient.openSession(Unknown Source)
	at com.mapr.drill.drill.client.DRJDBCClient.<init>(Unknown Source)
	at com.mapr.drill.drill.core.DRJDBCConnection.connect(Unknown Source)
	at com.mapr.drill.jdbc.common.BaseConnectionFactory.doConnect(Unknown Source)
	at com.mapr.drill.jdbc.common.AbstractDriver.connect(Unknown Source)
	at java.sql.DriverManager.getConnection(DriverManager.java:664)
	at java.sql.DriverManager.getConnection(DriverManager.java:270)

Looking at this line,

`private static final String CONNECTION_URL = "jdbc:drill:zk=192.168.1.1:31010/drill/dev.maprcluster.com-drillbits;schema=dfs";`

The documentation you provided a link to, stated it to be an example of connecting to a zookeeper cluster. And you copied the same server address provided in the example. There are many cluster managers like Yarn and Mesos. Ensure you are using the correct connection string to the right manager in your cluster and again, the server addresses should correspond to the respective addresses in your cluster.

Again, separate the aspect of the code that you want to use to get connection to a separate class and handle the logic in a single try-catch block, for the sake of separation of concern, instead of having it in a nested try-catch block in your service class.
This would enable you to test and debug more easily to understand what is happening.

Finally, since there's no static trace to inform of the error, the right approach is to debug the connection class (assuming you have extracted it out), then step through it to learn what is happening in that line. That would enable you to figure out what to do next.

I love Apache Drill, but is this really the best way to read Parquet data if you are worried about speed?

The AvroParquetReader might be a better approach for directly reading a Parquet-formatted file.

You can also use the ParquetFileReader class directly. Example here:

https://www.jofre.de/?p=1459

and here:

https://www.arm64.ca/post/reading-parquet-files-java/