Recent Posts
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Java – why does the clear HashMap method clear the map added in the array list
I'm trying to reuse the same HashMap, such as the following example to populate the list First, I add some values to t…… -
Java – ACL security in spring boot
I encountered a problem setting ACL through Java configuration in spring boot application I created a small project to…… -
Java – isn’t it bad to import unused packages?
For example, when you work in a team with the same file, you can only partially understand the different packages requ…… -
Is java “public static void main (string [] args)” the only way to create a main method?
I wonder if "Java main method" is the only way to create a main method in Java Java main methods: Solution The JVM nee…… -
Java – compile a multi module Maven project without installing it into a local repository
There is a compilation (and packaging) problem in my multi module Maven project There was a problem compiling one of t…… -
Update specific object items in array list Java
I want to ask a question, how do I update the records in the array list object: For example: List<User> userList…… -
Java generics: return bounded generic types
I follow this Code: public <T extends ParentException> T managedException(Exception cause) { if(Exce…… -
Java – how to use the return value of executorservice
I run the for loop under executorservice If any return type fails, I need to return resposne as "fail" or I need to re…… -
Why use bitwise or in catch blocks to handle exceptions in Java?
Why use bitwise OR here? try { //some errorprone code } catch(NullPointerException |NumberFormatExceptioon…… -
Assembly – vmovdqu what are you doing here?
I have a Java loop as follows: @ h_ 419_ 7@ public void testMethod() { int[] nums = new int[10]; for (int i = …… -
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Java – how to simulate an actor based on actorselection?
I have searched a lot about this, but there is no answer I have an actor "a" (user / a). When I receive the message "m…… -
Java – why must variables be initialized?
Here, I try to get the output month by entering the number of months, but why do I make a mistake Why must monthstring…… -
How to initialize 2D string array in Java
I know how to declare arrays. I've done this: String[][] board1 = new String[10][10]; Now I want to do this. By defaul…… -
The pre constructor initializes the properties of variables in Java
In Java, you can initialize programming variables before calling constructors public class StockGraph extends JPanel {…… -
Java – display integers on toast
I tried to display a toast message with an integer in it Toast.makeText(this,bignum,Toast.LENGTH_LONG).show(); But it …… -
How do I provide an implementation for enumeration values in Java?
I have the value of the enumeration class. Assuming that it will grow over time, I hope the user adding the new enumer…… -
Multithreading – can multiple threads write the same value to the same variable?
I understand the contention condition and how multiple threads access the same variable. Updates made by an update can…… -
Upgrade from A-Series to D-series azure virtual machines
We installed SQL sever.com on a series of virtual machines We want to upgrade to D series virtual machines Is it as si…… -
Java – ‘CMD’ is not recognized as an internal or external command and can run programs or batch files
When I build my project in NetBeans, it shows: 'cmd' is not recognized as an internal or external command,operable pro…… -
Java – hibernate condition groups start with timestamp by date
I have a table with a timestamp column and want to create a hibernate conditional projection. The results are grouped …… -
Java – how to use custom validation in Jersey
I want to implement verification in Jersey, so if I send a duplicate value of username or email that already exists in…… -
Java – activator 1.3 0 error on SBT project?
I'm happily working on some SBT projects. After I download and use the new version of typesafe activator, I can't open…… -
How to easily convert a two-dimensional array into a two-dimensional vector?
I'm focusing on rust wasm tutorial. I hope to easily add a ship (a real shape) to the universe in the game of life As …… -
Is java an import keyword for source or binary files?
I know I can use the import statement to include a class or group of classes in my java project For example, import Ja…… -
Java intelligently converts seconds into time
I want to create a library because I can't find one to convert seconds or milliseconds into time Well, I mean: 1) If I…… -
Java – s.equals (“”) and “” What’s the difference between equals (s)
First: s.equals ("") and "" What's the difference between equals (s)? Second: what if I want to perform one of these f…… -
java – ClassCastException：org. springframework. orm. jpa. Entitymanagerholder cannot be cast to org springframework. orm. hibernate5. SessionHolder
I tried to create a simple user login and registration page But I can't create users using the service method @Service…… -
Lambda function in Java 8 has no parameters and return values
I want to transform a simple Java function into a lambda 8 function without any parameters, and then call it: public i…… -
Is java “public static void main (string [] args)” the only way to create a main method?
I wonder if "Java main method" is the only way to create a main method in Java Java main methods: Solution The JVM nee…… -
Is there any way to generate content type headers from file extensions in Java?
I have a Java application that sometimes has to be changed from a file list to a content - type header Is there any wa…… -
Java Swing: separating UI components from logical behavior – how do you handle this?
What do I do in NetBeans, for example: >Create a UI component class with the suffix swing component type, for examp……