Java
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Java – unsupported major Minor version 49.0
When I log in to my application, I get the following exception What does that mean? How can I solve the problem? Solut…… -
Java – eclipse (using J2EE plug-ins) does not build class files into the output directory
I have several versions of eclipse that have this problem In some cases, eclipse does not output bytecode class files …… -
Java – can some unit tests be ignored?
I am developing a project that uses JUnit 4 widely in all modules We are using Maven 2 to build the project, and Hudso…… -
Is there any way to modify the value of the “private static final” field in Java?
I know it's usually stupid, but don't shoot me before reading this question I promise I have a good reason to do this:…… -
Simple natural language processing to start Java
See English answer > is there a good natural language processing library [closed] 3 Unfortunately, I didn't see any…… -
Java – integration test using redis
With the help of jedis library, I began to use redis.com in my project All work normally, but now I have a problem. My…… -
Java – how to apply spring boot filters based on URL patterns?
I created a spring boot filter – implementing genericfilterbean with the @ Component annotation @Component public cla…… -
Java – good practice for editing objects by reference?
Suppose I have a type called superstar Now I want to have a method to do some work and edit some properties of a super…… -
Java – how to package and run a simple dependency command line application using Maven?
I'm new Java and maven, so it may be simple If I follow Maven 2 Hello world's instructions: http://maven.apache.org/gu…… -
Objectmapper serialization in Jackson
I want to serialize different types of lists by using an object mapper, but I don't know how AccountingService accServ…… -
Java – how do I get a new stateful session bean in a servlet thread?
I'm experimenting with EJB3 I want to inject a stateful session bean into a servlet so that every user accessing the s…… -
Java: how to resolve lambda parameters of wildcard types?
Then we have a functional interface: public interface Consumer<T> { void accept(T t); } I can use it: .han…… -
Java – how to access managed beans and session beans from servlets
See the English answer > get JSF managed bean by name in any servlet related Class6 <p:dataTable value="#{myBean…… -
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Multithreading – why is the compareandswap instruction considered expensive?
Why is the compareandswap instruction considered expensive? I read a Book: "Memory impairment is expensive, like the e…… -
Java – how to easily submit neon using git in eclipse
I just upgraded from Mars to eclipse neon Previously, I could select submit from the team menu, and the dialog box wil…… -
Are there constants for language code in Java or Java libraries?
Do language codes in Java or Java libraries (such as "en" or "de") have constants? (or use string OK?) I know such thi…… -
Test whether the font is first-class in Java
I'm listing all the constant width fonts available on the user's machine I can get all fonts in swing in the following…… -
How to view the status of check boxes in the Java GUI?
I have about 200 check boxes in the Java GUI Now I want to list all the checkboxes that the user has checked I can do …… -
Memory – multithreaded heap management
In C / C + +, I can allocate memory in one thread and delete it in another thread However, as long as someone requests…… -
Java – automatically call superclass methods
Consider class class A{ public void init(){ //do this first; } public void atEnd()…… -
Java – distinguish between string args [] and string [] args
I've seen two different ways to declare a string array, but I don't show any difference Anyone can explain the differe…… -
Java – use interface classes as keys to get specific instance values?
I have the following test cases and can't retrieve values from the map: package tests; import java.util.HashMap; impo…… -
Java – use Apache POI to make columns read-only
I am using Apache POI to generate Excel files I need to make column 4 read-only, and the other 2 columns will be edite…… -
JavaFX: how to connect two nodes in a row?
I want to connect two nodes (from the center of the first to the center of the second) with a line Initial ideas: Supp…… -
Java Swing button color
See the English answer > how to set background color of a button in Java GUI? 7 Now my next stage is to add color t…… -
Java – the broadcastreceiver did not receive the action of completing the download
I'm trying to capture download completion events, but my broadcastreceiver doesn't receive them This is the receiver: …… -
Java: force two-way linked objects
I design a game engine in Java The core of this engine is that there are two types of assets and attributes, among whi…… -
Java – spring boot extends crudrepository
I'm at @ L_ 301_ 0 @ use hibernate in boot application I am creating a new crudrepository for all my model objects to …… -
Conditionally remove Java methods at compile time
I'm trying to implement something like a c# preprocessor I know that Java does not have the same preprocessor function…… -
Java – cannot send a multipart / mixed request to pop up MVC based rest services
I have a spring MVC and resteasy rest service. I need to test it by sending multipart / mixed requests The service cod…… -
Java – how do I sign Mac OS X applications in Linux?
For OS X, I distribute Java applications to DMG Due to the release of mountain lion, the following error message will ……