title: Error says variable already defined in main when trying to convert string to double then says unknown symbol
body: <p>I have looked for over 40 minutes trying to find an answer on this site that might pertain to my question to no avail.</p>
  
  <p>I am stumped.  I am trying to convert a program to GUI.  I am using Textpad which is telling me when I compile that the variable is already defined in main method.  Then when converting to int or double, it is telling me that it cannot find symbol and points to the variable that I am trying to convert.  Then during my calculations, it is telling me bad operands type for binary operator '*'.  </p>
  
  <pre><code>import javax.swing.JOptionPane;
  
  public class PayrollGUI {
  
  // calculates payroll
  public static void main (String [] args) {
  
  String name = JOptionPane.showInputDialog ("Employee's Name: ");
  int name = Integer.parseInt(nameString);
  
  String hours = JOptionPane.showInputDialog ("Number of hours worked in a week (e.g., 10: ");
  int hours = Integer.parseInt(hoursString);
  
  String payRate = JOptionPane.showInputDialog ("Hourly pay rate (e.g., .6.75: ");
  double payRate = Double.parseDouble(payRateString);
  
  String federalTaxRate = JOptionPane.showInputDialog ("Federal tax witholding rate (e.g., .20: ");
  double federalTaxRate = Double.parseDouble(federalTaxRateString);
  
  String stateTaxRate = JOptionPane.showInputDialog (" State tax witholding rate (e.g., .09: ");
  double stateTaxRate = Double.parseDouble(stateTaxRateString);
  
  //calculate witholdings, grosspay and netpay
  double federalWitholding = federalTaxRate * (hours * payRate);
  double stateWitholding = stateTaxRate * (hours * payRate);
  double grossPay = hours * payRate;
  double netPay = grossPay - withholdings;
  double witholdings = federalWithodling + stateWitholding;
  
  //format to keep two digit decimal
  witholdings = (int) (witholdings * 100) /100.0;
  netPay = (int) (netPay * 100) / 100.0;
  grossPay = (int) (grossPay * 100) / 100.0;
  federalWitholding = (int) (federalWitholding * 100) / 100.0;
  stateWitholding = (int) (stateWitholding *100) / 100.0;
  
  /*String output = (null);
  String output = (null);*/
  String output = "Employee Name: " + name +
  "/nHours Worked: "  + hours +
  "/nPay Rate: $" + payRate +
  "/nGross Pay: $" + grossPay +
  "/nDeductions:" +
  "/n     Federal Witholding: $" + federalWitholding +
  "/n     State Witholding : $" + stateWitholding +
  "/n     Total Deductions : $" + witholdings +
  "/n     Net Pay: $";
  JOptionPane.showMessageDialog(null, output);
  }//end main
  }//end Payroll
  </code></pre>