package br.com.jdbc;

import java.sql.*;

public class ConectaBanco {

    public static void main(String [] args) {
        try {
            Class.forName("oracle.jdbc.driver.OracleDriver");
            Connection con = DriverManager.getConnection("jdbc:oracle:thin:user/pass@host:1522/base");

            Statement stmt = con.createStatement();
            String sql ="Select * from acesso where nrdocumento ='999999999999'";
            ResultSet res = stmt.executeQuery(sql);

            while (res.next()); {
                String hash = res.getString(3);
                System.out.println(hash);
            }

            con.close();
        } catch (Exception e ) {
            e.printStackTrace();
        }
    }
}

finally {
    if(stmt != null) {
        stmt.close();
    }
    if(rs != null) {
        rs.close();
    }
    if(con != null) {
        con.close();
    }
}

stmt = con.createStatement();
sql = " SUA SEGUNDA QUERY COM HASH = '" + hash + "' ";
rs = stmt.executeQuery(sql);
while (rs.next()) {
    //leitura do resultado
}

public static void main(String [] args) {
    Connection con = null;
    ResultSet rs = null;
    Statement stmt = null;
    try {
        String sql = "";
        String hash = "";
        Class.forName("oracle.jdbc.driver.OracleDriver");
        Connection con = DriverManager.getConnection("jdbc:oracle:thin:user/pass@host:1522/base");

        stmt = con.createStatement();
        sql = " Select * from acesso where nrdocumento ='999999999999' ";
        rs = stmt.executeQuery(sql);
        while (rs.next()) {
            hash = rs.getString(3);
        }
        rs.close();

        stmt = con.createStatement(); //não tenho certeza se precisa chamar novamente
        sql = " SUA SEGUNDA QUERY COM HASH = '" + hash + "' ";
        rs = stmt.executeQuery(sql);
        while (rs.next()) {
            //leitura do resultado
        }
    } catch (SQLException e ) {
        e.printStackTrace();
    } finally {
        if(stmt != null) {
            stmt.close();
        }
        if(rs != null) {
            rs.close();
        }
        if(con != null) {
            con.close();
        }
    }
}