First of all, please read below blog post to understand basics of Exception Handling in java.
Exception handling and java keywords
To continue from there, Basically Java default API has hierarchy of java classes to support different uses cases of exceptions.
The parent class of all Exceptions and Errors is Throwable. Please check below pictorial representation of API Hierarchy.
Exception:
The class Exception and any subclasses that are also not subclasses of RuntimeException are checked exceptions.
And all subclasses of RuntimeException and RuntimeException class itself are Unchecked exception. Rest all are Checked exceptions
Examples of Unchecked Exceptions:
ArrayIndexOutOfBoundException
NullPointerException
Error:
An Error is a subclass of Throwable that indicates serious problems that a reasonable application should not try to catch. Most such errors are abnormal conditions.
Examples: The ThreadDeath error
