Conexão está com problemas

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.ArrayList;

private Connection con = null;

public BD() {
	try {
		Class.forName("oracle.jdbc.driver.OracleDriver");
		con = DriverManager.getConnection("jdbc:oracle:thin:@127.0.0.1:1521:XE", "iesde", "iesde");
	}catch(Exception e) {
		e.printStackTrace();
	}
}

public void closeBD(){
	try {
		con.close();
	} catch (SQLException e) {
		e.printStackTrace();
	}
}

public Boolean cadastraFornecedor(Fornecedor fornecedor) {
	String query = "INSERT INTO FORNECEDOR VALUES (?, ?)";
	PreparedStatement pst;
	try {
		pst = con.prepareStatement(query);
		pst.setInt(1, fornecedor.getCodigo());
		pst.setString(2, fornecedor.getNome());
		pst.executeUpdate();
		pst.close();
		
		return true;
	} catch (SQLException e) {
		e.printStackTrace();
		return false;
	}
}

public Boolean cadastraVendedor(Vendedor vendedor) {
	String query = "INSERT INTO VENDEDOR VALUES (?, ?)";
	PreparedStatement pst;
	try {
		pst = con.prepareStatement(query);
		pst.setInt(1, vendedor.getCodigo());
		pst.setString(2, vendedor.getNome());
		pst.executeUpdate();
		pst.close();
		
		return true;
	} catch (SQLException e) {
		e.printStackTrace();
		return false;
	}
}

public Boolean cadastraItem(Item item) {
	String query = "INSERT INTO ITEM VALUES (?, ?, ?, ?)";
	PreparedStatement pst;
	try {
		pst = con.prepareStatement(query);
		pst.setInt(1, item.getCodigo());
		pst.setString(2, item.getNome());
		pst.setString(3, item.getTamanho());
		pst.setInt(4, item.getFornecedor().getCodigo());
		pst.executeUpdate();
		pst.close();
		
		return true;
	} catch (SQLException e) {
		e.printStackTrace();
		return false;
	}
}