大约有 16,000 项符合查询结果（耗时：0.0464秒） [XML]
What is a NullPointerException, and how do I fix it?
...ou should know, Java types are divided into primitive types (boolean, int, etc.) and reference types. Reference types in Java allow you to use the special value null which is the Java way of saying "no object".
A NullPointerException is thrown at runtime whenever your program attempts to use a null...
What Every Programmer Should Know About Memory?
...spend the time reading the manuals about details about the actual timings, etc. But for people interested in the HW low level stuff? Maybe not useful, but at least entertaining.
– Voo
Nov 14 '11 at 18:52
...
Is quitting an application frowned upon?
... being
PUSHed to the device, lists with tasks
that always should be there, etc.).
I don't know what "lists with tasks that always should be there" means, but the "data being PUSHed to the device" is a pleasant fiction and should not be done by activity in any case. Use a scheduled task (via AlarmMa...
DDD - the rule that Entities can't access Repositories directly
... and specifications and so on), right? But if none of them are allowed to fetch data via Repositories, how am I supposed to write any (reasonably complicated) business logic? For example: Chatroom user is not allowed to change their name to a name thats already been used by someone else. I'd like th...
How would you implement an LRU cache in Java?
Please don't say EHCache or OSCache, etc. Assume for purposes of this question that I want to implement my own using just the SDK (learning by doing). Given that the cache will be used in a multithreaded environment, which datastructures would you use? I've already implemented one using LinkedHashM...
How can I perform a culture-sensitive “starts-with” operation from the middle of a string?
... length of the substring that was actually matched. But Compare, IndexOf ..etc
throw that information away. It could be possible with regular expressions but the implementation doesn't do full case folding and so doesn't match
ß to ss/SS in case-insensitive mode even though .Compare and .IndexOf do...
How do I clone a subdirectory only of a Git repository?
... you are interested, search for discussions on "sparse clone" and "sparse fetch" on the git mailinglist.
In general, the consensus in the Git community is that if you have several directories that are always checked out independently, then these are really two different projects and should live in ...
Why do we need private subnet in VPC?
...stance (i.e you don't have multiple NAT instances configured for failover, etc.) which is generally true for most small to medium use case scenarios. Assuming a monthly data transfer of 100GB via the NAT gateway,
Managed NAT instance monthly cost = $33.48/month ($0.045/hour * 744 hours in a month) ...
What is the purpose of the reader monad?
...eneralizedNewtypeDeriving extension to derive Functor, Applicative, Monad, etc. for newtypes based on their underlying types.
– Rein Henrichs
Jan 18 '14 at 19:02
add a comment...
What and where are the stack and heap?
... the processor translates to physical addresses and there are page faults, etc. They keep track of what pages belong to which applications. You never really need to worry about this, though, because you just use whatever method your programming language uses to allocate and free memory, and check ...