6 files declare their use of JsonValidationException

Application.php in vendor/composer/composer/src/Composer/Console/Application.php
ConfigValidator.php in vendor/composer/composer/src/Composer/Util/ConfigValidator.php
DiagnoseCommand.php in vendor/composer/composer/src/Composer/Command/DiagnoseCommand.php
Factory.php in vendor/composer/composer/src/Composer/Factory.php
InitCommand.php in vendor/composer/composer/src/Composer/Command/InitCommand.php
JsonConfigSource.php in vendor/composer/composer/src/Composer/Config/JsonConfigSource.php