Java
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Java – advantages of log4j
The advantage of log4j is that the system Out and system Err set to output to log file? Solution At a high level, log4…… -
Java – why use J_ Username and spring_ SECURITY_ LAST_ Username variable?
Why do things turn out like this? <input type="text" name="j_username" value="${SPRING_Security_LAST_USERNAME}">…… -
Java series reel to disk
Because some very large lists and collections are built during a transaction, I ran out of memory in Java and repeated…… -
Java – how to add a JDBC MySQL driver to an eclipse project?
There is already an answer to this question: > how to install jdbc driver in eclipse web project without facing Jav…… -
Java – does pdfbox support spot color and color separation?
I am interested in using it in the project PDF@R_635_2419 @, the project needs to be able to specify spot color and co…… -
Java – collect Linux command output
I'm on a @ L_ 404_ 0 @ on the machine I have a java program that will run some linux commands, such as PS, top, list o…… -
Java – how do I get a custom space between JList projects?
I've added several images to my JList, and now I'm showing their level. Now I want to increase the space between the i…… -
java – System. Out character encoding
I run my java program from the command line (Windows 7) To simplify matters, I will only describe the relevant parts p…… -
Java – is the constructor not a member of a class?
Constructor is not a member of class? If so, why not inherit? JLS 7.0 says that constructors are not members, so they …… -
Ultra lightweight Java persistence layer needs
I need a super lightweight persistence layer for the Java application I'm writing I need it to become a stand-alone ap…… -
Java – how does method parsing and invocation work inside Python?
How do method calls work in Python? Indeed, python method parsing in Python may be slower than Java What is late bindi…… -
Calling Java functions from clojure
I can use (. Touppercase "good") because "good" is a Java string that has a touppercase method I can also use (Java. I…… -
Java – PostgreSQL error: undeclared due to user request
What causes this error in PostgreSQL? org.postgresql.util.PsqlException: ERROR: canceling statement due to user reques…… -
Java – detect mouse movement on the screen
I created a mousemotiondetection class, which just detects whether the user has moved the mouse anywhere on the screen…… -
. Net – complex query of ORM (especially NHibernate) performance
Our company is rewriting the existing application from scratch This application and other tasks perform complex SQL qu…… -
Java – IntelliJ: search the project for the source of Maven dependencies
Can I search some text through the source code of all Maven dependencies of the project? For example, if you import th…… -
How to use generics in Java to reference nested types?
How do I create generic classes that reference nested generic types? I'm trying to create a comparator class that can …… -
Java – why not use the element zero of the heap array?
This is the beginning of my rough sketch of a heap with arbitrary values 0 1 2 3 4 5 6 7 8 9…… -
Java – why choose JMS for asynchronous resolution? Why is it better than a simple entity bean?
In most of the projects I participated in, the choice of asynchronous solution has always been the source of a lot of …… -
Java – get threads waiting indefinitely
I have a java thread to handle outgoing communication with the socket I just want the thread to run, and the pending o…… -
Java – why does type promotion take precedence over varargs of overloaded methods
public class Test public class Test { public static void printValue(int i,int j,int k) { System.out.pr…… -
Is the Java virtual machine language agnostic?
To be sure, the Java virtual machine was originally designed for the Java programming language, but now other develope…… -
Java – logger slf4j does not have the level configured with logback
My log record is through logback Configuration of logback using groovy files Now, when my Maven POM project aggregates…… -
java – Objects. Requirenonnull (t obj) instead of null check and throw illegalargumentexception manually?
Whenever I check whether the given parameter of a method is not null, if the null check fails, I use it to write a nul…… -
Java robot keyboard command key
VK of command key on MAC_ [key] what is the code? I tried to get a Java robot to press the command key I'm using the c…… -
Java – Maven plugin build failed when using Lambdas
I wrote a maven plugin / mojo to generate some code The plug-in runs well and has built-in Java JDK 1.8 I see some str…… -
Java generics and wildcards are compiled in eclipse, but not in javac
As a follow-up Java genetics compile in eclipse, but not in javac, I released another code segment compiled and runnin…… -
Java – smack client – the user is still online even though the connection is aborted
I use smack to build a small XMPP client / BOT to experience a very strange behavior I set up a connection and a conne…… -
Multiply by two vectors – I want a scalar, but I get a vector?
This is my code: a <-c(1,2,3) b <-t(a) print(a*b) I expect the result to be 14, because the multiplication of th…… -
Java – returns a string from JMS
I'm writing an independent main method that calls a producer (pushing data into a queue) and then calls a consumer who…… -
Array – the goal of combining LinkedList with string reverse is to understand LinkedList
I tried to use a link list program to display the reverse string entered by the user Here is my program to reverse the…… -
Java – use Apache POI to read the contents of the drop-down list from excel
I need to create a drop-down list (data validation) on a specific cell in the excel worksheet and read it back With th……