Is it possible to use Serial window for debug statements while using the hardware serial port for GPS module?
Is it possible to print the debug statements in the Serial window while the GPS module is connected to the hardware serial ports?


Yes, that works.  If you connect the Arduino TX pin 1 to the GPS RX, then everything you print to Serial goes to both the Serial Monitor window and the GPS device.

This works, because:


It's ok if you see the GPS configuration commands (if any) on the Serial Monitor window.  Your debug prints will appear after them.
The GPS device ignores anything that doesn't start with a '$' character; it ignores all your debug prints.