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Can enums be subclassed to add new elements?
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No, you can't do this in Java. Aside from anything else, d would then presumably be an instance of A (given the normal idea of "extends"), but users who only knew about A wouldn't know about it - which defeats the point of an enum being a well-known ...
tcp端口状态ESTABLISHED、TIME_WAIT、CLOSE_WAIT 、SYN_RECV等详解 - C/C++...
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net.ipv4.tcp_fin_timeout 修改系統默认的 TIMEOUT 时间
查看系统TCP连接资源命令
netstat
netstat -n | awk '/^tcp/ {++S[$NF]} END {for(a in S) print a, S[a]}'
一般情况下，系统的socket资源默认5000个。（非官方）
Windows Dos命令：netstat -an | find "端...
How to break out or exit a method in Java?
The keyword break in Java can be used for breaking out of a loop or switch statement. Is there anything which can be used to break from a method?
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Best way to work with dates in Android SQLite [closed]
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Always make sure to store the UTC/GMT time, especially when working with java.util.Calendar and java.text.SimpleDateFormat that use the default (i.e. your device's) time zone.
java.util.Date.Date() is safe to use as it creates a UTC value.
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Converting Long to Date in Java returns 1970
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tl;dr
java.time.Instant // Represent a moment as seen in UTC. Internally, a count of nanoseconds since 1970-01-01T00:00Z.
.ofEpochSecond( 1_220_227_200L ) // Pass a count of whole seconds since the same epoch...
Java SafeVarargs annotation, does a standard or best practice exist?
I've recently come across the java @SafeVarargs annotation. Googling for what makes a variadic function in Java unsafe left me rather confused (heap poisoning? erased types?), so I'd like to know a few things:
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Split Java String by New Line
...gex, limit) with negative limit like text.split("\\r?\\n", -1). More info: Java String split removed empty values
– Pshemo
Jul 19 '16 at 13:08
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Intersection and union of ArrayLists in Java
... This post could use an update to demonstrate the benefits of the Java 8 Stream API.
– SME_Dev
Sep 2 '15 at 15:57
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What are fail-safe & fail-fast Iterators in Java
There are two types of iterators in Java: fail-safe and fail-fast.
4 Answers
4
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What makes JNI calls slow?
I know that 'crossing boundaries' when making a JNI call in Java is slow.
3 Answers
3
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