Handling "Cannot Format Given Object as a Date" Error in Java

When attempting to convert a given date into a specific format, Java developers may encounter the exception: "java.lang.IllegalArgumentException: Cannot format given Object as a Date." This error occurs when trying to format an unsupported object as a date.

To resolve this issue, we need to use the correct formatting strategy. The DateFormat.format method accepts Date objects as input. In the provided example, the input value is a string representing a date, not a Date object.

The solution is to use two separate SimpleDateFormat objects: one for parsing the input string and another for formatting the result. For instance:

// Define the output format (mm/yyyy for months and years)
DateFormat outputFormat = new SimpleDateFormat("mm/yyyy", Locale.US);

// Define the input format (yyyy-MM-dd'T'HH:mm:ss.SSSX)
DateFormat inputFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSX", Locale.US);

String inputText = "2012-11-17T00:00:00.000-05:00";

try {
    // Parse the input string as a Date object
    Date date = inputFormat.parse(inputText);

    // Format the Date object using the desired format
    String outputText = outputFormat.format(date);
} catch (ParseException e) {
    // Handle parsing exceptions here
}

By following this approach, we can effectively convert a string representing a date into a desired format while avoiding the "Cannot format given Object as a Date" error.