Java error handling code is separate from the code for normal processing.

Errors generate an exception object representing the error. This is called throwing an exception. A thrown exception terminates a Java program unless it is caught and handled properly at some level of the application.

Both Java API classes and custom-created classes can throw exceptions. In fact, users can create their own exception classes that throw their own custom-created classes.

If there is no exception handler in the body of the method where the exception occurred, then the search for an exception handler continues up the call stack. If the top of the call stack is reached and no exception handler has been found, the default exception handler of the Java interpreter running the application is called and the program terminates.

In SQL Anywhere, if a SQL statement calls a Java method, and an unhandled exception is thrown, a SQL error is generated. The full text of the Java exception plus the Java stack trace is displayed in the server messages window.