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java: (String[])List.toArray() gives ClassCastException
... IntelliJ, I get a warning to use toArray(new String[0]) rather: "In older Java versions using pre-sized array was recommended as the reflection call which is necessary to create an array of proper size was quite slow. However since late updates of OpenJDK 6 this call was intrinsified, making the pe...
How to run a background task in a servlet based web application?
I'm using Java and I want to keep a servlet continuously running in my application, but I'm not getting how to do it. My servlet has a method which gives counts of the user from a database on a daily basis as well as the total count of the users from the whole database. So I want to keep the servlet...
Java: Best way to iterate through a Collection (here ArrayList)
...
There is additionally collections’ stream() util with Java 8
collection.forEach((temp) -> {
System.out.println(temp);
});
or
collection.forEach(System.out::println);
More information about Java 8 stream and collections for wonderers link
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javac option to compile all java files under a given directory recursively
I am using the javac compiler to compile java files in my project. The files are distributed over several packages like this: com.vistas.util , com.vistas.converter , com.vistas.LineHelper , com.current.mdcontect .
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JPanel Padding in Java
I have a formatting question for my Java swing application. It should be fairly straightforward, but I am having difficulty finding any aid (Every topic seems to be regarding removing any default padding in JPanel). The text in my various JPanels hug the sides and top, touching the colored borders...
Map to String in Java
When I do System.out.println(map) in Java, I get a nice output in stdout. How can I obtain this same string representation of a Map in a variable without meddling with standard output? Something like String mapAsString = Collections.toString(map) ?
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Java: using switch statement with enum under subclass
...te that I'm much more familiar with enums in C# and it seems like enums in java is a quite mess.
6 Answers
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Office在线预览及PDF在线预览的实现方式大集合 - 更多技术 - 清泛网 - 专注...
...独的服务器（可以是虚拟机），配置过低能安装，但无法运行，另外还需一台域服务器。而这两台机器上均不能安装其它程序，比如SQLServer，在Office365服务器上每次重启IIS会重置，也就是说你不能有任何其它网站。其主要是用来...
What's the difference between JPA and Spring Data JPA?
...PA and JPA. I know about JPA that it is a specification for persisting the Java Objects to a relational database using popular ORM technology.
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Is it possible to assign numeric value to an enum in Java?
Is anything like this possible in Java? Can one assign custom numeric values to enum elements in Java?
5 Answers
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