How do i change this piece of code from a double to a stirng

I am doing this for a school project and would like the user to be able to enter in yes if they would like to view the instructions if they would like. i have the rest of the program working but right now it is just letting them enter a number and i can not find out how to let them input a word without errors.

public void actionPerformed(ActionEvent e)
{
Double name, instructions;
name = Double.parseDouble(nameTF.getText()); //We use the getText & setText methods to manipulate the data entered into those fields.
instructions = Double.parseDouble(instructionsTF.getText());

}

That's a strange UI idea - entering "yes" for boolean decision. The proper way if for the user to click a checkbox, the label of which says "view instructions" or some such.

Try a string compare,
if( answer == "yes") then myNumber = 1 else myNumber = 0

Something like that.