Exception and error handling in java
	-unexpected or abnormal event
	-belongs to parent class called throwable
	-checked exception(must be caught,example File Classes)
		and unchecked exception(example 10/0, nothing to be caught)
	-try catch finally or try with resources
	-refer to slides for information leakage specific to errors

errorneous exceptional behaviors
	-suppress or ignoring checked exception-
		dummy blocks that does nothing but to fullfill the criteria
	-disclose error information-printstacktrace
	-logging sensitive data
	-ensure that logging process should not be disrupted by throwing incorrect exceptions
	-use java.util.logging.logger instead of System.err
	-for System.exit(), use security manager to check if the caller is valid to invoke the method
	-nullpointerexception should not be caught but should be solved, do not solve problem by simply appying nullpointerexception in the catch clause
	-code inside finally block can also throw error, so, don't let them to escape but handle them as well

dos and donts in error handling
	-avoid direct usage of Exception class in the catch block
	-avoid printstacktrace
	-use logger file to log the error
	-do not use same exceptions for different function throws, leads to difficulty in debugging
	-cleanup in the finally

spring mvc error handling
	-controller level exception handler
		-add @exceptionhandler annotation
			-include the list of exceptions
		-implementing handlerexceptionresolver
			-override resolveexception method
	-global exception handler
		-use @controlleradvice annotation with @exceptionhandler for any class
	-custom errors mapping
		-use @enablewebsecurity annotation and websecurityadapter
struts2 error
	-global exception handling
		-refer slides for configuration sample
	-action level exception handling
		-define the class name and action name in the struts.xml file
		-refer slides for configuration example
	-logging
		-for logging the exception, add an interceptor to struts.xml file
		-refer slides for configuration example
best practices for error handling
	-throw relevant error to its interface
	-specify the reason for the exception
	-encapsulate the error received from another function
		-use getCause to find the root exception
	-catch errors specifically so that handling can be done separately and specifically
	-create custom error page for all exceptions-no information leakage from default page

logging in java
	-provided by java.util.logging
	-LOGGER->FORMATTER-HANDLER(Apache Commons Logging,Log4J)
logging with log4j
	-contains levels such as DEBUG,INFO,WARN,ERROR,FATAL,OFF
secure coding in logging
	-don't log and then throw errors
	-do either one only
	-parameterized logging using SLF4J, don't use + for merging informations
	-log exceptions in proper order
best practices in logging
	-logging can increase IO operations, so , log debug messages inside isdebugenabled() block
	-use log4j, logging levels can be changed without restarting the application
	-do not log sensitive data when logging in production enviroment
	-do appropriate level for every logging messages
	-specify the format for logger, which includes thread name and class name
	-specify the date with the messages
	-use code level prefix to indicate which part of the code is
	printing the message