Java
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Java – how to avoid resetting fileuploadfield at the end of a request in wicket
I have a wicket form with fileuploadfield and more text fields Verification of correctness fails when required fields …… -
Java – why do fuzzy errors occur when using varargs overloads of primitive types and wrapper classes?
See English answers > ambiguous varargs methods4 Case 1 public class Test { public void display(int a) { …… -
Java – libgdx changes the color of the texture at run time
In a game made with libgdx, I have a textureatlas in which I store all textureregions for player animation By default,…… -
How to inject @ named bean into JUnit test
I'm trying to inject @ named bean into JUnit test This applies to my EJB module, but the same method in my war module …… -
Entity Framework – Entity Framework optimistic concurrency exception
Should I maintain the timestamp property on my model class to enable optimistic concurrency for data updates and delet…… -
Java – maven – cannot activate a configuration file in a multi module project
I have encountered some difficulties in configuring our project with Maven and need some help:) For example, I have a …… -
Equivalent to computeifabsent in Java 7
Is there any way to run a piece of code only when there is no key in the concurrenthashmap and save the results of the…… -
Java – how to make the callable task submit to executorservice timeout
I submit the callable task (using submit()) to the implementation of executionservice Occasionally I seem to encounter…… -
Java – xStream serializes null values
Suppose I have class Student { String name; int age; String teacher; } then: public class App1 { public static …… -
Java – use the domain alias account in appengine to send e-mail
I created an App Engine Application owned by x@foo.com. Foo. COM is a Google App account I've also added bar to the Go…… -
Should variables always be declared using interfaces in Java?
People often see the suggestion that variables should be declared with an interface rather than implementing a class F…… -
Java – how do WhatsApp and instant messaging applications run in the background without persistent notifications in Oreo?
What did I learn from stack overflow and Android documentation Unable to create background service for continuous task…… -
Java – deserialization version conflict
My question is, what is a good way to upgrade obsolete objects? For example, suppose you have a class like this: publi…… -
JavaFX – use FX: ID as CSS ID in fxml
It seems that if no ID (CSS) is specified in F XML, the FX: ID value is used by default My previous understanding is t…… -
How to modify the month value of dateformatsymbols
I'm trying to add a specific month name for a specific locale For example, the code is generated in January, February,…… -
Java – drawerlayout on the actionbar
When using drawer layout, is there any way to overlay the drawer view on the operation bar? I don't want to hide the a…… -
Java – how is it possible to use @ retention annotation recursively?
In the source code of @ retention annotation in Java, @ retention is used in its definition, which is possible Even re…… -
Java – how to build a basic terminal from scratch
I have checked some suggestions or instructions including stack overflow online, but anything I find is overwhelming. …… -
How to delete “is” from a Boolean getter generated by JAXB
JAXB is generating the following methods: Many class methods are generated, so it is not feasible to customize the gen…… -
java – Random. Problems with nextgaussian()
Random. Nextgaussian () should give a random number no.s, with a mean of 0 and an STD deviation of 1.0 Solution A Gaus…… -
Java – regular expressions ignore new lines and match only the entire large string?
I have this string here: CREATE UNIQUE INDEX index555 ON SOME_TABLE ( SOME_PK ASC ); I want to match mult…… -
Java 9 multi module Maven project test dependencies
I have a multi module Maven project, which contains three modules: core, utils and test utils The core has the followi…… -
Java – rotate the matrix into position
I'm solving the problem of rotating NxN matrix It seems that my code is rotating, but it leaves an X on the image. So …… -
Java – when to use akka microkernel?
I'm reading the akka document and I'm curious that some things haven't been well explained Their mention is called akk…… -
Add Java 9 system module and compile in eclipse
I have some legacy java code, namely: package org.alo.test.j9; import javax.activation.DataHandler; // in java.activ…… -
Java – hibernate only updates some fields
In some cases, I want to update only one column, but I don't want to get the object from the database. I only have its…… -
How to run programs in Java forever? System. in. Is read () the only way?
I took this Code: 28 public static void main(String[] args) throws IOException { 29 HttpServer httpServer…… -
Java – why do most web hosting services only support PHP as a server-side language?
I've been using Java and python, so I found a good web host that supports these But my question is, why can you find s…… -
Java – spring boot: handle multiple requests at the same time
I use spring boot to build a restful web service My IDE is eclipse oxygen I send HTTP get requests every 2 seconds thr…… -
Java – preload WebView in activity a and pass it to activity B to speed up loading
In one of my applications, I use WebView to load the page. The scenario is that I have activity a and activity B. acti…… -
What does this Java generic paradigm do and what is it called?
I'm looking at some Java classes with the following forms: public abstract class A <E extends A<E>> imple…… -
Java – using thread Sleep() limits the frame rate
I'm making dynamic wallpaper, so don't worry about physical collision I just want to keep the frame rate as smooth as ……