Recent Posts
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Java – optimistic locking and org hibernate. StaleObjectStateException：
I'm just trying to be optimistic I have the following courses: @Entity public class Student { private Integer id;…… -
Java: enumeration and if then else performance
I didn't have real luck. I used Google to get this concise answer rather than my time-consuming evaluation. I thought …… -
How do I catch all checked exceptions (in a single block) in Java?
Editor: this problem only involves Java 1.6 (and below) I'm sorry I didn't make it clear in the original post The hier…… -
Java – how to make Maven build fail on duplicate dependencies?
If I have two identical dependencies in the same POM, I want the build to fail At present, I can use Maven dependency …… -
Java – where can I find the base64encoder class?
Hi, I saw an example with this code on stackoverflow: String encoding = Base64Encoder.encode ("test1:test1"); HttpPost…… -
Java – spring boot devtools gets ClassCastException from the cache
I'm having trouble getting value from the cache java.lang.RuntimeException: java.lang.ClassCastException: com.mycom.ad…… -
Java – change date format
If the input is 01-01-2015, it should be changed to 2015-01-01 //Class to change date dd-MM-yyyy to yyyy-MM-dd and vic…… -
Java – accessing private fields of another object in the copy constructor – is that really a problem?
In my java application, I have some such copy constructors public MyClass(MyClass src) { this.field1 = src.field1;…… -
Java-8 – delete the “05:30” section from java8 localdatetime to xmlregistry calender
As shown below, LocalDateTime currentUTCTime = LocalDateTime.Now(ZoneId.of("UTC")); String reqPattern = currentUTCTime…… -
Java – preconditions library throws illegalargumentexception for notnull check
Do you know that Apache commons validate or guava preconditions is a good alternative. When checking whether the objec…… -
In Java / Apache httpclient, you cannot use vertical / pipe bars to process URLs
If I want to handle this URL, for example: post = new HttpPost("http://testurl.com/lists/lprocess?action=LoadList|4018…… -
Java – spring data: can I include subqueries in query annotations?
I wonder if subqueries (org. Springframework. Data. JPA. Repository. Query;) can be used in the @ query annotation I g…… -
Java – static initializer and instance initializer and constructor
There is already an answer to this question: > use of initializers vs constructors in java8 Solution The main diffe…… -
Java – classloader will not be garbage collected even if there is no GC root
We have one in GlassFish v2 Complex applications running under 1.1 In order to dynamically load our code, we implement…… -
Java – a handler that does not add an HTTP header to an HTTP request when using the axis client API
I am using the axis API to access the axis HTTP server I use the following code to add a handler to the server The typ…… -
Java – why get base class methods through reflection when subclasses override them?
I have super classes: class MyClass<T> { public void setValue(T value){ //insert code } public T getV…… -
Java – how to read BufferedReader two or more times?
I have a text file, one integer per line – 10 20 50 I want to read and print these numbers twice or more I tried some …… -
Java – what happens when l (long) – = f (float)?
See English answers > floating point arithmetic not producing exact results 7 public class SimplePrint { public st…… -
Java – what does “reference implementation” mean?
I'm trying to learn the cachedrowset in Java, and I'm reading some tutorials about it for example Who can please be ki…… -
Java – Bayesian network in Scala
I am looking for a library to create Bayesian networks and learn and reason in scala (or Java, if there is no better s…… -
Java – overrides tostring() using overridden tostring()
Basically, that's what I want to achieve classname @ address(？) [original tostring()], the name of the object and the…… -
Java – JPA – delete children from the onetomany relationship
In the @ onetomany relationship, if I want to delete a child, do I need to explicitly delete the child from the parent…… -
How do I inform users that a specific tab in jtabbedpane needs attention?
Suppose you have a user interface with five or more tabs and you need to notify the user that tab "2" needs attention …… -
The target version of java compiler “jsr14” and JDK7 / 8
Who can tell me that javac with jsr14 target option can still use JDK7 / 8? Say, $javac -source 1.5 -target jsr14 Hell…… -
Java – when to use hibernate connection. provider_ class
When should I use hibernate connection. provider_ class？ Me and 'hibernate connection. diver_ There is a bit of confu…… -
Java – how to export all my IntelliJ code styles to Editorconfig file?
I tried to develop a standard code style for my project, and I've found it http://editorconfig.org/ , this is a standa…… -
java – inputstream. Available() is always 0
I don't know what happened to my code I made no mistakes and did not respond I'm writing data to serialport and activa…… -
JSF. Load and invoke supported bean methods on each page
See the English answer > invoke JSF managed bean action on page load4 I have pages with datasheets and several bean…… -
How to perform different operations in update() of observer in Java?
I just started using observable, observer and its update () method. When different actions call notifyobservers (), I …… -
Multithreading – find tutorials and information on load balancing between threads
I know that the term "load balancing" may be very broad, but the topic I'm trying to explain is more specific. I don't…… -
Java 64 bit JDK problem
If I compile some java files using the 64 bit JDK and then create a jar file from them, do the generated jars use the …… -
Use the start process and wait commands in PowerShell
I'm new to power shell. I don't have much programming background. I just try to use it for software packaging Anyway, ……