Null vs Blank vs Empty

    public static void handleNullChecks(){
        List<Account> accList = [Select Id, Rating from Account Where Id = '001J400000KjIboIAF'];
        if(accList.size() > 0){
            System.debug(accList[0]);
        }
	}

    public static void handleBlankScenarios(){
        String var1;
        String var2;

		System.debug(String.isBlank(var1)); //True
        System.debug(String.isEmpty(var2)); //True
        System.debug(var1 == null); //True
        System.debug(var2 == null); // True
        
        var1 = '';
        var2 = '       ';

		System.debug(String.isBlank(var1)); //True
        System.debug(String.isBlank(var2)); //True
		System.debug(String.isEmpty(var1)); //True
        System.debug(String.isEmpty(var2)); //False
        System.debug(var1 == null); //True
        System.debug(var2 == null); //True
        System.debug(var1 == null); //False
        System.debug(var2 == null); // False
        
    }