Java Coding Problems

Instantiating a class via a private constructor

The Java Reflection API can be used to instantiate a class via its private constructor as well. For example, let's suppose that we have a utility class called Cars. Following best practices, we will define this class as final and with a private constructor to not allow instances:

public final class Cars {  private Cars() {}    // static members}

Fetching this constructor can be accomplished via Class.getDeclaredConstructor(), as follows:

Class<Cars> carsClass = Cars.class;Constructor<Cars> emptyCarsCnstr = carsClass.getDeclaredConstructor();

Calling newInstance() at this instance will throw IllegalAccessException since the invoked constructor has private access. However, Java Reflection allows us ...