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infoJava ErrorsAffects: All versions

How to Fix NumberFormatException

Fix NumberFormatException by finding and correcting invalid number values in Minecraft configuration files.

Quick Fix

Check the config file mentioned in the error and fix any invalid number values.

Error Message

java.lang.NumberFormatException: For input string

How to Fix

1

Open the configuration file mentioned in the stack trace

2

Find and fix any non-numeric values where numbers are expected

3

Delete the config file and let it regenerate with defaults

4

Check server.properties for invalid port or other numeric values

Common Causes

  • Invalid number in a configuration file
  • Corrupted server.properties or mod config
  • Using text where a number is expected

Diagnostic Steps

  1. Read the error message for the invalid input string
  2. Check config files for that invalid value
  3. Replace it with a valid number
  4. Restart

FAQ

Which config file should I check?

The stack trace will point to which mod or file has the problem. Common places: server.properties, mod config files in config/ folder.

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