MissingFormatArgumentException

Why This Happens

String.format() and System.out.printf() throw this exception when the format string contains more %s, %d, or other specifiers than there are corresponding arguments. Each specifier must have a matching argument.

The Problem

String msg = String.format("Hello %s, you have %d messages from %s", "Alice", 5);
// Missing third argument for the third %s

The Fix

String msg = String.format("Hello %s, you have %d messages from %s", "Alice", 5, "Bob");

Step-by-Step Fix

1. 1

   Identify the format string

   Find the String.format() or printf() call and count the format specifiers (%s, %d, %f, etc.).

2. 2

   Count the arguments

   Count the arguments after the format string and compare with the number of specifiers.

3. 3

   Add missing arguments or fix the format

   Provide the missing arguments, or remove extra format specifiers from the format string.