While accessing the CLOB data (approx size 1305 KB) from Oracle DB getting null value through JDBC

Question

The code is deployed on JBOSS server sitting on LINUX Environment. Below is code to access the CLOB data from oracle using JDBC API.

JDBC jar used is ojdbc6.jar. JAVA version : jdk1.8.0_221-amd64 Oracle java verion : 1.8.0_121

import java.sql.Clob;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.io.IOException;
import java.sql.ResultSet;
import java.sql.SQLException;

public class GetGenericPDFData {

     public String GetPDFData(String SolutionID) throws IOException {

           String PDFData = null;

           try {

                Class.forName("oracle.jdbc.driver.OracleDriver");
                Connection con = DriverManager.getConnection("jdbc:oracle:thin:@ServerIP:1521:SID","username","password");

                String Query = "select pdf_data from stage1.pdf_queue where system_id in (select system_id from (select * from pdf_queue where solution_id = ? 
and status = 'Completed' order by time_stamp desc) where rownum=1)";

                PreparedStatement preparedStatement = con.prepareStatement(Query);
                preparedStatement.setString(1, SolutionID);

                ResultSet rs = preparedStatement.executeQuery(); 

                while(rs.next()){

                     PDFData = rs.getString("pdf_data");

                }

                //Below data is coming out as null
                System.out.println(PDFData);

                con.close();

           } catch (ClassNotFoundException | SQLException e) {
                // TODO Auto-generated catch block               
                System.out.println("GetGenericPDFData.GetPDFData 7");               
                e.printStackTrace();            
                PDFData = "false";              
           }

           return PDFData;
     }

}