NewInstance

NewInstance<T> creates objects through public constructors. Interfaces cannot be instantiated.

String value = new NewInstance<>(String.class).newInstance();

StringBuilder builder =
        new NewInstance<>(StringBuilder.class, "text").newInstance();

When arguments are supplied, the constructor is currently selected by their exact runtime classes. A public constructor accepting a superclass or interface is therefore not matched from a subtype argument. Parameters containing null also require an explicitly obtained Constructor.

The class argument must be non-null and concrete. Interfaces are rejected explicitly; abstract classes fail later during constructor invocation.

Constructor helpers

getConstructor(Class<T>, Class<?>...) returns an exact public constructor and throws RuntimeException if it cannot be found. newInstance(Constructor<T>, Object...) invokes an already selected constructor and preserves the original failure as its cause.

Constructor<String> constructor =
        NewInstance.getConstructor(String.class, String.class);
String value = NewInstance.newInstance(constructor, "text");

hasArgsCon(Class<?>) reports whether the class exposes at least one public constructor with parameters.

Non-public constructors are outside this utility's supported scope. Passing a null Constructor is not validated explicitly and currently produces NullPointerException.