Usage of the methods of Throwable requires that the class be extended and that a subclass of Throwable will have access to the methods of its superclass. Throwable has four constructors:

Throwable()
Throwable(String message)
Throwable(String message, Throwable cause)
Throwable(Throwable cause)

Also, as a superclass, Throwable has several methods which are available to all classes which inherit from it:

getMessage()—Returns a message associated with the exception/error
toString()—Returns a String containing a description of the Throwable object

printStackTrace()—Prints the string return by toString() followed by the execution stack trace showing the sequence of a method invocations that led to the exception being thrown