RFR: Add utility for creating objects via factory method when unable to create via constructor

[Kyle J Stiemann]

Adds CLI option to provide a factory FQCN which can create objects that you want to analyze. This is useful in situations where you have dependency classes or JDK classes that require non-null objects or have other validation in the constructor. These kinds of classes can't easily be modified, so it's nice to provide an alternative option for creating them.

For example:


    public static final class RequiresFactory {
       public RequiresFactory(final String string) {
           Objects.requireNonNull(string);
           if (string.isEmpty()) {
               throw new IllegalArgumentException("string must not be empty");
           }
       }
    }


Usage:


java -jar jol-cli.jar internals --classpath my-classes.jar --factory my.Factory my.RequiresFactory


Where `my.Factory` is:


public class Factory {
    public static <T> T newInstance(Class<T> aClass) {

        if (aClass.equals(RequiresFactory.class)) {
            return aClass.cast(new RequiresFactory("test"));
        }

        throw new UnsupportedOperationException(aClass.getTypeName());
    }
}

-------------

Commit messages:
 - Add utility for creating objects via factory method when unable to create via constructor

Changes: https://git.openjdk.org/jol/pull/58/files
  Webrev: https://webrevs.openjdk.org/?repo=jol&pr=58&range=00
  Stats: 154 lines in 7 files changed: 143 ins; 0 del; 11 mod
  Patch: https://git.openjdk.org/jol/pull/58.diff
  Fetch: git fetch https://git.openjdk.org/jol.git pull/58/head:pull/58

PR: https://git.openjdk.org/jol/pull/58