Output formatted number to jTextField

Question

I am new to Java and am building a desk top application. I perform the calculations and get the correct answer in the jTextField; however, I have been unable to get the answers to format. The numbers are "doubles" at this point in the calculations. I have tried several different variations of the code I am posting below and nothing works. All the answers I have found on the web and in books are set up for a System.out.println() answer as opposed to putting the answer in a jTextField. I believe the problem is between the formatting and putting the answer into the jTextField, but am uncertain. I would appreciate any suggestions to alleviate this problem.
Thanks - Bob
if ( M1 > M2) {
NumberFormat numberFormat = NumberFormat.getInstance();
DecimalFormat decimalFormat = (DecimalFormat)numberFormat;
decimalFormat.applyPattern("0.### ### ### ### ### ### ###");
jTextField3.setText(String.valueOf(MDiff));
jTextField4.setText(String.valueOf(EDiff));
else {
NumberFormat numberFormat = NumberFormat.getInstance();
DecimalFormat decimalFormat = (DecimalFormat)numberFormat;
decimalFormat.applyPattern("###,###,###,###,###,###,###");
jTextField3(setText(String.valueOf(MDiff));
jTextField4.setText(String.valueOf(EDiff));
}

Answer 1

The numbers are entered as text, and then converted to a "float" variable. They are then changed to "double" and multiple computations take place. The code that I posted is after the computations of MDiff and EDiff, and covered the "logical if" where I test to see which of two numbers from the initial data entry was larger and format appropriately. There was error in my post which I have corrected. The error was in the 4th line below "else" where it states: "jTextField3(set....." I have changed it to read "jtTextField3.set....", and it builds without error. Sorry about that.
As previously stated, I get correct answers from the computations, but am unable to format the answers.
Bob