All exceptions are subclasses of a class called java.lang.Throwable.
In Core Java, the base class from which all exceptions are subclasses is the java.lang.Throwable class. Throwable is the superclass of all errors and exceptions in the Java programming language. There are two main subclasses of Throwable: Error and Exception. All other exception classes in Java extend either Error or Exception (or their subclasses).
So, the correct answer to your question would be Throwable.