Recent Posts
-
How to select random numbers in a range, but weight them to a part of the range? (in Java)
I want to choose a random number from a series of numbers, but I want to weight part of the range For example: >Sel…… -
Java – the code is compiled in eclipse, but not from the command prompt
The following code has no problem compiling in eclipse using JDK7 (I use update 10, but it should be used with any ver…… -
Java – is there any way to know the type of object?
The scheme is that I pass an object as a parameter in the method, and I want to perform the operation according to the…… -
How to execute “javac and Java commands” from a java program?
Is there any way to execute "javac and Java commands" from Java programs? If so, please help me Solution Like runtime …… -
Java – generics – what am I missing or what’s the point?
I have the following code: public class AClass<X extends AnInterface> implements AnotherInterface { public …… -
How to return values from methods that contain arrays in parameters in Java?
I have this code, but it doesn't work! public class Trial { public static void main (String [] args) { …… -
Improve performance when working with images in Java
I'm writing a program that includes an image folder (usually about 2000 JPEG images) to resize them and add them to th…… -
Java – common code when rewriting abstract methods – Design Problems
I have an abstract class like this public abstract Stuff { public abstract void doStuff(); } Several classes are e…… -
Java observer update function
I have a class that implements the observer. Of course, it needs to have the update function: public void update(Obser…… -
Java Object. equals
Can someone tell me why this returns true? Please tell me under which topic I can find more information about this beh…… -
Java – arrange swing components by edge
Can swing components be arranged? You can see a subtle difference that I find very annoying I know that all jlabels [B…… -
Set vs alphabetical order in Java list
Arent lists ordered collections and is not ordered? So why does this program sort strings alphabetically instead of li…… -
Correcting Java program code snippets
I'm a beginner. I learn Java and modify my exam by answering the questions in the past exam papers. There's another qu…… -
Java – concurrent HashMap document description
Concurrent HashMap is fully interoperable with hashtable in programs that depend on its thread safety but not on its s…… -
Hexadecimal enumeration types use java to return wrong values?
I use the following enumeration types in the following code: public static enum PanelType { PAS8((byte)0xA6),PAS83…… -
Java Swing: add jlabel to JPanel
I just want to add jlabel to the existing JPanel It looks simple. I searched everywhere I think this is right, but the…… -
How to compare two string arrays without Java utils
Check whether array Arr1 contains the same elements as arr2 in the same order in Java For example: isTheSame({"1","2",…… -
The try catch block cannot suppress Java lang.NullPointerException
I got Java Lang.nullpointerexception, I don't know why I tried to use the try catch block, but it didn't work Can anyo…… -
Java monitoring: JMX and servlets
In the past few years, I have learned a lot about JMX and built some very beautiful MBeans for my web applications But…… -
Java – JNI local reference table summary (512 entries)
I have more than 10000 city names that I want to display in listview I store these names as cities in the RES / values…… -
Loop stop Java
For the following code, when "n" is about 100000, it will stop running I need it to run to a million I don't know what…… -
Java – how to wait for all callables to complete execution before continuing?
I have the following hash code: public class MyCallable implements Callable<Long> { @Override public Lon…… -
Java character set / character encoding
I have a Spanish file, so it is full of the following characters: á é í ó ú ñ Ñ Á É Í Ó Ú I have to read the document,…… -
Java – @ entity entity cannot be resolved to a type
Learn spring MVC and hibernate import javax.persistence.Column; import javax.persistence.GeneratedValue; import javax.…… -
Java – OOP design – Private modifier
I thought I knew when to use the private keyword Encapsulation is the reason for this, so I try to keep all methods as…… -
Java – how to programmatically launch Apache Derby jar files?
I have a Java application that uses Apache Derby Using the eclipse export option, I export it as a jar file When I run…… -
Java – HibernateException: the proxy handle is no longer valid after the database violation error
I have a loop to hold several objects Invoke the service method in the loop and catch the exception. The service saves…… -
Java – XML error due to servlet file. The declaration of the element cannot be found, and the referenced file contains an error
I don't know why these mistakes happen. Someone can explain how I solve them – > cvc-elt. 1: Element 'Web' not foun…… -
Dropwizard / Jersey returns the Java list as JSON without a root node
I'm using the dropwizard using plain knit fabric for Jason My problem is that when I return a list, it does not specif…… -
Java: how to communicate with multiple clients in a single thread
I have a list of sockets belonging to a single thread But I wonder if there is a feasible way to communicate (read / w…… -
Java – do we have all the original types of pools in the permgen area of the heap?
I know the concept of string pool in permgen area of heap So when we do something like this String firstString = "Stac…… -
Java – use generics to return multiple types
I have this method – public List<Apples> returnFruits(String arg1){ List<Apples> fruits = new ArrayList<……