public static void isNull (final Object aValue, @Nonnull final Supplier <? extends String> aName)
  {
    if (isEnabled ())
      if (aValue != null)
        throw new IllegalArgumentException ("The value of '" + aName.get () + "' must be null but is " + aValue);
  }
public static void isNull ( final Object aValue , @ Nonnull final Supplier < ? extends String > aName ) { if ( isEnabled ( ) ) if ( aValue != null ) throw new IllegalArgumentException ( "The value of '" + aName . get ( ) + "' must be null but is " + aValue ) ; }
Check that the passed value is <code>null</code>.

@param aValue
The value to check.
@param aName
The name of the value (e.g. the parameter name)
@throws IllegalArgumentException
if the passed value is not <code>null</code>.