file.go

package main

import (
	"fmt"
	"os"
)

func IncorrectCloseFile(json_data []byte) {
	//create json file
	json_file, err := os.Create("sample.json")
	if err != nil {
		fmt.Println(err)
		// Not stop the process
	}
	defer json_file.Close()

	json_file.Write(json_data)
	// File had already been closed in Line#15, use the defer smart and correct
	json_file.Close()
}

// You can choice to not return the error out, but it's good to have the error for the caller
func CloseFile(json_data []byte) error {
	//create json file
	json_file, err := os.Create("sample.json")
	if err != nil {
		fmt.Println(err)
		return err
	}
	defer json_file.Close()

	json_file.Write(json_data)
	return nil
}