Exception in thread “main” java.lang.Error: Unresolved compilation problems

Hi every one i have some problem in my jdbc code i am trying to connect through mysql but it will give error.my error log is given below if you have some time please help me.

Exception in thread "main" java.lang.Error: Unresolved compilation problems:
    BLOB cannot be resolved to a type
    BLOB cannot be resolved to a type

    at serialize.SerializeDeserialze.main(SerializeDeserialze.java:73)
my code is given below.... i am using mysql-connector-java-5.1.20.jar driver

package serialize;
 By vivek


import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

import oracle.sql.BLOB;

CREATE TABLE java_objects (object_id NUMBER, object_name varchar(128), object_value BLOB DEFAULT empty_blob(), primary key (object_id));
SQL> desc java_objects;
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 OBJECT_ID                                 NOT NULL NUMBER
 OBJECT_NAME                                        VARCHAR2(128)
 OBJECT_VALUE                                       BLOB


------------------------------ ---------- ---------- ------------ -----------
ID_SEQ                                  1 1.0000E+27            1          21
JAVA_OBJECT_SEQUENCE                    1 1.0000E+27            1           1

public class SerializeDeserialze {
  public static void main(String[] args) throws Exception {
        + "  INSERT INTO java_objects(object_id, object_name, object_value) "
        + "  VALUES (?, ?, empty_blob()) " + "  RETURN object_value INTO ?; " + "END;";
    String READ_OBJECT_SQL = "SELECT object_value FROM java_objects WHERE object_id = ?";

    Connection conn = getOracleConnection();
    List list = new ArrayList();
    list.add("This is a short string.");
    list.add(new Integer(1234));
    list.add(new java.util.Date());

    // write object to Oracle
    long id = 0001;
    String className = list.getClass().getName();
    CallableStatement cstmt = conn.prepareCall(WRITE_OBJECT_SQL);

    cstmt.setLong(1, id);
    cstmt.setString(2, className);

    cstmt.registerOutParameter(3, java.sql.Types.BLOB);

    BLOB blob = (BLOB) cstmt.getBlob(3);
    OutputStream os = blob.getBinaryOutputStream();
    ObjectOutputStream oop = new ObjectOutputStream(os);

    // Read object from oracle
    PreparedStatement pstmt = conn.prepareStatement(READ_OBJECT_SQL);
    pstmt.setLong(1, id);
    ResultSet rs = pstmt.executeQuery();
    InputStream is = rs.getBlob(1).getBinaryStream();
    ObjectInputStream oip = new ObjectInputStream(is);
    Object object = oip.readObject();
    className = object.getClass().getName();

    // de-serialize list a java object from a given objectID
    List listFromDatabase = (List) object;
    System.out.println("[After De-Serialization] list=" + listFromDatabase);

  private static Connection getHSQLConnection() throws Exception {
    System.out.println("Driver Loaded.");
    String url = "jdbc:hsqldb:data/tutorial";
    return DriverManager.getConnection(url, "sa", "");

  public static Connection getMySqlConnection() throws Exception {
    String driver = "org.gjt.mm.mysql.Driver";
    String url = "jdbc:mysql://localhost/demo2s";
    String username = "oost";
    String password = "oost";

    Connection conn = DriverManager.getConnection(url, username, password);
    return conn;

  public static Connection getOracleConnection() throws Exception {
    String driver = "oracle.jdbc.driver.OracleDriver";
    String url = "jdbc:oracle:thin:@localhost:1521:databaseName";
    String username = "userName";
    String password = "password";

    Class.forName(driver); // load Oracle driver
    Connection conn = DriverManager.getConnection(url, username, password);
    return conn;
asked May 7, 2015 in Core java by rajesh
0 votes

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