MySQL Database Query in JAVA

Question

I'm a beginner and have done multiple successful queries to my database in JAVA but one of my queries is returning something that I don't understand. What's printing is: [Ljava.lang.String;@6b081032 And what actually should be printing are names of conditions. So if my query is suppose to return 7 condition names, it will print "[Ljava.lang.String;@6b081032" seven times.

Below is my code where I'm testing out a method that I've been having a problem with. What does "[Ljava.lang.String;@6b081032" mean? Thanks.

public class Test {
 static String url = "jdbc:mysql://localhost:3306/masters";  //providing the host, port and database name
    static String username = "christine";
    static String password = "password";

    static PreparedStatement pst = null;
    static ResultSet rs = null;

    public static void main(String[] args) throws IOException{

        String[] test = dxNameByName(2);
            for(int i=0; i<test.length; i++)
                {   
                    System.out.println(test);
                }

}


public static String[] dxNameByName(int num){

    Connection con = null;
    ArrayList<String> list= new ArrayList<String>();     
    String[] result = new String[list.size()];           

    try{
        con = DriverManager.getConnection(url, username, password);  //establishes a connection to the database
        pst = con.prepareStatement("SELECT * FROM diagnosis WHERE  diag_region_fk = '" + num+ "';");                                                                                                                                                
        rs = pst.executeQuery(); 

            while (rs.next())                   
            {                                   
                list.add(rs.getString("diagnosis_name"));
            }
         result = list.toArray(result);     
         }catch(SQLException e){     
             e.printStackTrace();    
         }
             finally{
        try { if (rs != null) rs.getStatement().close(); } catch (Exception e) {};
        try { if (pst != null) pst.close(); } catch (Exception e) {};
        try { if (con != null) con.close(); } catch (Exception e) {};
    }

return result;

}
}

Why make the computer go to all of the trouble of building an ArrayList, and then just return an array? — le3th4x0rbot
– le3th4x0rbot, Commented Apr 28, 2013 at 21:18

syb0rg · Accepted Answer · 2013-04-28 21:21:57Z

1

You are printing the array itself, not the contents of the array. Use Arrays.toString():

System.out.println(Arrays.toString(test));

That gives the nicest looking output IMHO (example: [something, something, something]).

You could also iterate through all the values and print them one at a time:

for(int i=0; i<test.length; i++)
{   
    System.out.println(test[i]);
}

The output is a little less nice though, since each content is printed on it's own line.

edited Apr 28, 2013 at 21:21

answered Apr 28, 2013 at 21:15

syb0rg

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blackpanther · Accepted Answer · 2013-04-28 21:44:04Z

1

[Ljava.lang.String;@6b081032

this means that the printed variable type is String[]

In order to output the result of the query, change your code to the following:

System.out.println(test[i]);

edited Apr 28, 2013 at 21:44

blackpanther

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answered Apr 28, 2013 at 21:15

WeMakeSoftware

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