First you have to know the name of the package containing the class. If you know it, you can try the following:
String className = packageName + ".Test";
Class cls = Class.forName(className);
cls.getMethod("main", String[].class).invoke(null);
Note that, if the class is in (default) package then you can use “Test” as className without the package name.
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solved java string to class and call mathod