An example missing from the documentation is that `ReflectionClass::isInstantiable` will also return false for traits, as well as interfaces and abstract classes.<?phptrait t { // Optional trait methods and properties etc.}$reflectionClass = new ReflectionClass("t");var_dump($reflectionClass->isInstantiable()); // bool(false)?>As for classes with private constructors, it is still possible to create an instance by either bypassing the constructor using `ReflectionClass::newInstanceWithoutConstructor`, or by ensuring the class has a method which can create a new instance.<?phpclass p { private function __construct() { // Optional constructor logic - not called when ReflectionClass::newInstanceWithoutConstructor is used. } public static function create() { return new p; } // Optional methods and properties etc.}// Class is not classed as instantiable.$reflectionClass = new ReflectionClass("p");var_dump($reflectionClass->isInstantiable()); // bool(false)// We're still able to create an instance using one of the two methods.$p = p::create();$p = $reflectionClass->newInstanceWithoutConstructor();?>The same is also true for protected constructors, however, the class can be instantiated from either parent or child methods, depending on where the constructor is defined.<?phpclass p { protected function __construct() { // Optional constructor logic. } public static function create( $class = "" ) { if (!$class) { $class = get_called_class(); } return new $class; } // Optional parent methods and properties etc.}class c extends p{ // Optional child methods and properties etc.}// Both child and parent static methods have access to each other's protected constructor.$p = c::create("p");$c = p::create("c");// Both are still not classed as being instantiable.$reflectionClassP = new ReflectionClass("p");$reflectionClassC = new ReflectionClass("c");var_dump($reflectionClassP->isInstantiable()); // bool(false)var_dump($reflectionClassC->isInstantiable()); // bool(false)// We're still able to bypass the constructor and create an instance for each.$p = $reflectionClassP->newInstanceWithoutConstructor();$c = $reflectionClassC->newInstanceWithoutConstructor();?>