private java.sql.Connection con = null;
private PreparedStatement pst = null;
private ResultSet rs = null;
private String url = "jdbc:mysql://localhost:8889/deliveryEarn";
private String user = "root";
private String password = "root";

try {
     con = DriverManager.getConnection(url, user, password);
     Statement st = (Statement) con.createStatement();

     st.executeUpdate("INSERT INTO incomeCalc " + "VALUES (3, 75, 6, 25, 18.50)");

     con.close();
}

catch (SQLException ex) {
     Logger lgr = Logger.getLogger(deliveryMain.class.getName());
     lgr.log(Level.SEVERE, ex.getMessage(), ex);

 }

INSERT INTO incomeCalc VALUES (3, 75, 6, 25, 18.50)  // error
// the only way this will work is when you have only 5 columns in
// your table but in your case you have 7 that is why it wll not work

INSERT INTO incomeCalc(specify columns here to the values bound to)
VALUES (3, 75, 6, 25, 18.50)

INSERT INTO table_name
VALUES (value1, value2, value3,...)

INSERT INTO table_name (column1, column2, column3,...)
VALUES (value1, value2, value3,...)

"INSERT INTO incomeCalc(ID, TIPS, HOURS, GAS, HOURLY_EARNINGS) " +
"VALUES (3, 75, 6, 25, 18.50)"

"INSERT INTO incomeCalc (ID, TIPS, HOURS, GAS, HOURLY_EARNINGS) VALUES (3, 75, 6, 25, 18.50)"

ps = "INSERT INTO incomeCalc(ID, TIPS, HOURS, GAS, HOURLY_EARNINGS) VALUES (?, ?, ?, ?, ?)"

ps.setInt(index++, id); //id=3
        ps.setInt(index++, tips); //tips=75
        ps.setInt(index++, hours);//hour=6
        ps.setInt(index++, gas);//gas=25
        ps.setFloat(index++, HOURLY_EARNINGS);

INSERT INTO TABLE_NAME (COLUMN_NAMES_SEPARATED_BY_COMMA) VALUES (VALUES_SEPARATED_BY_COMMA)