txtRate.setText(emp.getRate());
I cant display the data from the csv file in the textbox because it keeps on saying
double cannot be converted to java.lang.String. My method is public Double getRate() If i try to make is public String it would work but i cant use the value for calculation because it already has been set to String
The class you are working on contains method with signature setText(String value) but there's no method with signature setText(Double value).
When you call a method compiler checks the parameter type and tries to recognize what method should be in use for this case.
As you are using Double type for the parameter, the compiler is unable to find a method with signature setText(Double value) and you get the error you have reported in your question.
To overcome this issue, convert your parameter from Double to String type before passing it to setText method.
txtRate.setText(String.valueOf(emp.getRate())); or
txtRate.setText(emp.getRate().toString()); But the second approach may throw NullPointerException if emp.getRate() returns null, so the first approach is safer.
In case you want to format your numbers in a fancy way, consider this tutorial: https://docs.oracle.com/javase/tutorial/java/data/numberformat.html
Displaying data on the textbox require variable to be string, But calculation require variable to be double the answer is when displaying cast to string and when calculation don't
