Java
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Java – unable to instantiate log4j appender
I'm following a tutorial on log4j logging in web applications This is my log4j Properties file: #log to console log4j.…… -
Java – how to map a class to different tables using hibernate / JPA annotations
At present, my persistence seems to be a very simple problem, but I can't seem to find a way: I have two identical tab…… -
Drawing java with canvas
I want to draw Java canvas, but I can't make it work because I don't know what I'm doing This is my simple code: impor…… -
Java – a shorter method for dynamically obtaining the name of the current method
See English answer > getting the name of the current executing method18 This is what we are doing now: new Object()…… -
Java – immutable objects and spring / sring MVC: the right choice?
I usually try to design my courses as immutable classes, so I have many advantages in programming stress However, when…… -
How do I use selenium webdriver and Java to close a specific window?
I use selenium webdriver I open the first page and then the second - do something and go back to the first page Before…… -
Java – high performance JMS messaging
I read the slide from this year's uberconf. One of the speakers is arguing that spring JMS adds performance overhead t…… -
java – URLConnection setRequestProperty vs addRequestProperty
Let me say I'm talking about HTTP to a web server. I will accept HTML or text, but I prefer HTML In other words, the t…… -
Java – use wildcards to create new generic objects
Please explain the compilation time error of this generic code wildcard: //no compile time error. List<? extends Nu…… -
Java – play! The framework returns a JSON response
I use play! Framework 2.0 and I are new in this framework How to return only the JSON representation of my model in a …… -
Java – dependency management and maven
I recently became a big fan of Maven to control the build cycle of my application However, I encountered some rough ed…… -
Java – enables NetBeans (ANT) to generate multiple jar files for a project
I have a NetBeans project with two main classes. One starts a client and the other starts a server I need to create tw…… -
Learn Java, so I can get clojure
I have a history of hating Java. In the "slow ball" era, I often used it in the late 1990s Therefore, I never really u…… -
java – Spring Batch：org. springframework. batch. item. Reader notopenexception: the reader must open it before reading
I read about the problem, but the solution didn't work for me I got org springframework. batch. item. Reader not opene…… -
Java – unable to resolve symbols for powermockrunner
I tried powermock for the first time I use build Gradle and add: dependencies { ... testCompile 'org.mockito:mocki…… -
Java – write toString () once and for all?
I want all my classes to implement toString () in the same way using java reflection I came up with two ways >Creat…… -
Java – how to manually map enumeration fields in jax-rs
How to map a simple JSON object {"status": "successful"} to Java enum in jax-rs automatically? public enum Status { …… -
DFA Based regular expression engine with captured Java
Is there any (free) regular expression engine for Java that can compile regular expressions into DFA and capture combi…… -
Java – why doesn’t class have a good generic type in this case?
In this code, why can't you declare a type as class? Extension b > public class Foo<B> { public void doSo…… -
Java – local or instance members
The following code proves that method1 is faster than method2 Anyone can comment on the reasons for this behavior clas…… -
Rxjava / rxbinding: how to handle errors on rxview
I use RX Java and rxbindings to view in Android Here's an example of what I'm doing RxView.clicks(btMyButton).flatMap(…… -
Java – detect mouse entry / exit events anywhere in JPanel
Basically, there is a JPanel. I want to know when the mouse enters the JPanel area and exits the JPanel area So I adde…… -
Different users under Linux are preferred for Java system
I try to run multiple JVMs (including Tomcat) of different users on a Linux frame I don't see too many problems, but i…… -
java – Gson：JsonSyntaxException on date
I tried to deserialize a JSON array using gson, but I'm getting a jsonsyntaxexception The JSON string is generated by …… -
Java – how to get crc64 distributed computing (using its linear properties)?
I need to spread over large files stored on distributed FS I can handle parts of the file better than the whole file, …… -
When trying to read a file in HDFS from Java, “wrong FS… Expected: File: / /”
I can't read files from HDFS using Java: String hdfsUrl = "hdfs://<ip>:<port>"; Configuration configuratio…… -
Multithreading – is the method pointer assignment thread safe?
Example: Suppose I have the following clues (please do not consider the contents used in the thread context execution …… -
Java – = and =
I've been misplaced = many times, I think I've always forgotten, because I don't know the difference between the two. …… -
Java – hotswaping code to “mvndebug Tomcat: run”
Usually I use mvndebug Tomcat: run to start Tomcat After the code changes, I need to use MVN Tomcat: redeploy This is …… -
Java – how to pass map parameters or objects to post requests through transformation?
I encountered a problem passing a map parameter or object to a retrofit post request I follow square, kdubb labs tutor…… -
Java. Java in JDK class lang.ref. Memory leak of WeakReference object
The following simple code reproduces Java. Java in the heap lang.ref. Growth of WeakReference objects: public static v…… -
Glassfish 3.1. 2 JDBC realm has a new password encryption algorithm field what is it?
The GlassFish JDBC realm has several different properties that you can set I'm interested in digest algorithm and pass……