Validate for collections

[valery1707]

This arguments description:

public class Args {
    @Parameter(
        names = {"-a", "--app", "--root"},
        validateValueWith = ExistsDirectoryReadable.class
    )
    private List<File> application = Arrays.asList(
            new File("/srv/"),
            new File("/")
    );
}

will block parsing argument values with exception:

Exception in thread "main" java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48)
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:87)
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:50)
        at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51)
Caused by: java.lang.ClassCastException: java.util.Arrays$ArrayList cannot be cast to java.io.File
        at name.valery1707.jcommander.validators.io.ExistsDirectoryReadable.check(ExistsDirectoryReadable.java:7)
        at name.valery1707.jcommander.validators.ValueChecker.check(ValueChecker.java:18)
        at name.valery1707.jcommander.validators.ValueChecker.validate(ValueChecker.java:11)
        at com.beust.jcommander.ParameterDescription.validateValueParameter(ParameterDescription.java:285)
        at com.beust.jcommander.ParameterDescription.validateValueParameter(ParameterDescription.java:275)
        at com.beust.jcommander.ParameterDescription.validateDefaultValues(ParameterDescription.java:165)
        at com.beust.jcommander.ParameterDescription.init(ParameterDescription.java:158)
        at com.beust.jcommander.ParameterDescription.<init>(ParameterDescription.java:73)
        at com.beust.jcommander.JCommander.addDescription(JCommander.java:550)
        at com.beust.jcommander.JCommander.createDescriptions(JCommander.java:522)
        at com.beust.jcommander.JCommander.parse(JCommander.java:280)
        at com.beust.jcommander.JCommander.parse(JCommander.java:265)
        ... 9 more

Tested with jcommander:1.48 and jcommander-validator-io:0.1.11 under spring-boot:1.5.16.RELEASE