what is null pointer exception

Who's going to help me see what's wrong with this? uncaught exception ' smartyexception ' with message ' unable to write F Fatal error:uncaught exception ' smartyexception ' with message ' Unable to write File/usr/local/nginx/test/runtime/templa tescache_c/wrt4f6961cc176326.15312366 ' In/usr/local/nginx/test/vender/smarty/sysplugins/smarty_internal_write_ File.php:44 Stack Trace: #0/usr/local/nginx/test/ve

Error indicates system-level errors and exceptions that the program does not have to handle, an internal error in the Java Runtime environment, or a hardware problem. For example: insufficient memory resources and so on. For this kind of error, the program is basically powerless, except to exit the operation has no choice, it is thrown by the Java virtual machine.Exception (violation) indicates an

First, you define a class that displays validation information.Such as:1 Public InterfaceReturnobject {2 3 Public Booleanissuccess ();4 5 PublicString GetReason ();6 7 }8 9 Public classDefaultreturnImplementsReturnobject {Ten Private Booleansuccess; One PrivateString reason; A - PublicDefaultreturn (Booleansuccess, String reason) { - This. Success =success; the This. Reason =reason; - } - - @Override + Public Booleanissuccess () { - r

Difference between error and exception: Error indicates that recovery is not an impossible but difficult case. For example, memory overflow. It is impossible to expect the program to handle such a situation; Exception represents a design or implementation problem. That is to

Note: This article has been deprecated. For details about the revision, see:( Http://interma.cnblogs.com/archive/2006/01/01/309325.html) ---------------------------------------- This problem suddenly occurred at night and may be one of the following two situations:[1] The whole process (Program) All died.[2] the thread that throws an exception will die silently without affecting other threads. I tried it immediately. It turns out that [1]

Here I will write a little bit of my opinion. Exception Handling can be said to be the packaging of errors made by the Programming experts for the problems we encounter. We need to know more about errors than ourselves, If we use an if else statement to judge the case, we cannot judge all the cases. Even if we can judge the case, it will take a lot of effort. If we accidentally write a wrong judgment, it is