How to Get Primary Key Column from a Table

package example.jdbc.key;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
 
public class Main2 {
 
    public static void main(String[] args) throws Exception {
	Connection conn = getHSQLConnection();
	System.out.println("Got Connection.");
	Statement st = conn.createStatement();
	st.executeUpdate("create table survey (id int,name varchar, PRIMARY KEY (id) );");
	st.executeUpdate("insert into survey (id,name ) values (1,'nameValue')");
 
	ResultSet rs = null;
	DatabaseMetaData meta = conn.getMetaData();
	// The Oracle database stores its table names as Upper-Case,
	// if you pass a table name in lowercase characters, it will not work.
	// MySQL database does not care if table name is uppercase/lowercase.
	//
	rs = meta.getPrimaryKeys(null, null, "survey");
 
	java.util.List list = new java.util.ArrayList();
	while (rs.next()) {
	    String columnName = rs.getString("COLUMN_NAME");
	    System.out.println("getPrimaryKeys(): columnName=" + columnName);
	}
 
	st.close();
	conn.close();
    }
 
    private static Connection getHSQLConnection() throws Exception {
	Class.forName("org.hsqldb.jdbcDriver");
	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/octopus";
	String username = "root";
	String password = "root";
 
	Class.forName(driver); // load MySQL driver
	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:caspian";
	String username = "mp";
	String password = "mp2";
 
	Class.forName(driver); // load Oracle driver
	Connection conn = DriverManager.getConnection(url, username, password);
	return conn;
    }
 
}