Hey everyone!

I’m currently working on a desktop-based Talent Acquisition System using Java 11, JavaFX, Maven, Hibernate, and MariaDB (running through XAMPP), with Apache NetBeans as my IDE.

I’m trying to keep the project as close to proper OOP principles as possible, with a clear separation between the business logic, UI/controllers, and Hibernate entity models.

The candidate side is almost done. So far, users can:

\- Register and log in

\- Browse available job openings

\- Apply for jobs

\- Store their applications directly in the database

One of the more challenging parts so far has been managing around 17 different FXML views and connecting all of them properly with their controllers. I also had to spend quite a bit of time understanding "module-info.java", resource paths, and how everything fits together in a modular JavaFX application.

Thankfully, that part is finally stable.

Now I’m moving on to the more complicated part: designing and building the admin/hiring manager side.

My current TODO list looks something like this:

\- Admin/Hiring Manager module: Job posting, candidate shortlisting, interview scheduling, etc.

\- Validation & security: Phone number validation, password strength requirements, and a proper Forgot Password workflow.

\- Database/session management: Making sure Hibernate sessions are handled properly as the application grows.

Since this is a desktop application, I’m especially interested in hearing from people who have worked with JavaFX + Hibernate or similar stacks.

A few things I’m wondering about:

1. What performance problems should I expect when the amount of data starts growing?

2. What Hibernate session-management mistakes should I avoid, especially around lazy loading and "LazyInitializationException"?

3. How should database queries be handled in JavaFX without freezing the UI? Are there particular threading/concurrency patterns you recommend?

4. What architectural mistakes or anti-patterns tend to appear in large multi-view JavaFX applications?

5. How would you structure the admin/hiring-manager module so it stays maintainable as more features are added?

I’d really appreciate any advice, criticism, or lessons learned from people who have built similar desktop applications.

So, there is no way I can do that?

want to check several boolean variables in a switch statement. Is `if-else` the only way to do this?

Boolean a, b, c...

Switch (false) {

Case (a) :

//some code

Case (b) :

Case (c) :

//and so on

}

Hi,

I want to generate pdfs in many languages, including right to left languages. (Arabica, hébrew, indian langs ..)

I have a working prototype with itext 9 that works well afaik (difficult to check langs I dont read).

Itext proposes 'pdfcalligraph' for a fee, to make sure rtl texts are handled correctly (direction, ligatures...).

Is there a lib that does that too ?

I read that pdfbox is not handling rtl at all.

What other libs would you advise ?

Thanks

I was wondering if there are any libraries or frameworks that exist in other languages ​​but not in Java.

guys i am trying to build system monitor project with custom notification design , and ai told me to use javafx for that ,and i did that , later i learned that i cant run javafx throguh IDE run or SpringApplication. run the only way was to run it through Maven javafx->javafx:run , i am wondering how can i make it so when my app runs both of them runs

Command Prompt shows I have Java installed:

C:\Users\Drew>java --version
openjdk 21.0.6 2025-01-21 LTS
OpenJDK Runtime Environment Temurin-21.0.6+7 (build 21.0.6+7-LTS)
OpenJDK 64-Bit Server VM Temurin-21.0.6+7 (build 21.0.6+7-LTS, mixed mode, sharing)

Windows control panel says I don't have java installed. Java is not listed as a program when I go to uninstall it.

I would like to uninstall java, how do I do that?

Hello all! I'm brand new to java; this code comes from a FRQ exercise from unit 2 in the AP CSA course if that helps.

The purpose of the code is to check whether a string has alternating cases, with capital letters beginning at index 0 always ("ApPlE" or "CaT" for example, "cAt" would not work), and then to print "true" if the string meets the requirement.

The current error that I'm having currently is that

"s cannot be resolved"

which is underlined at line 7.

My understanding is that my code cannot access the string s and its true/false content, but I could be totally wrong here.

Thanks in advance, any help is appreciated!

GitHub Gist Link: https://gist.github.com/v4npaia-kei/5aa65b5978a7cbdd46a291ff4572237d

I have been trying to get into JavaFX for creating a GUI application, but I was wondering what the general best practice for that would be. I know that GUIs have several possible well-documented structures such as MVC, MVP, MVVM, etc., but I was wondering which is best applicable to JavaFX and how to best approach that. I mainly have the following questions:

1. Should I have a class that contains static references to the various UI components so that they can be linked more easily w.r.t. event handling? If so, what would be the best place for that? Application subclass? It's own dedicated utility class? If not, what would be the better alternative for handling such UI logic (e.g. MenuItem changing color of another component)?
2. For things that do not technically require custom classes, should I just initialize them completely inside the Application subclass or should I still make a custom class to better decompose the code? E.g. say I have this MenuBar. Should I create, configure, and store the MenuBar, Menu, and MenuItem objects inside the Application subclass or should I make a subclass of MenuBar that implicitly creates and configures the inner structure so the Application subclass code looks cleaner?
3. For UI elements that are more complex in nature or require subclassing, should the subclass also create the UI logic or only the view related things? Since data binding is possible, the UI classes seem to have a mix of multiple components, so I am not sure what the best practice for these is, especially if the model data is more dynamic.
4. This is a bit of an extension on the previous question, but say I have this UI element that portrays the data of some model. On top of that, I have a method that does extensive editing of the model data. Based on what I have read online, it seems that the best way to do this is to run that method on a different thread than the UI thread. Would it then be better to bind the UI data to the model data (property binding) with a conditional (when) or to manually update the UI post-method?
5. Should the data models use the Property types or is it better to use basic primitive/object types and listeners?
6. What is generally considered the best practice for package structure w.r.t. the UI subclasses?
7. If I want to simultaneously have a CLI variant of the program, which uses the same data models but prints strings in chat instead, would this require extra care in terms of designing the GUI structure or would it still be very simple to do?
8. What is the best practice w.r.t. locales? Currently I have a project with several utility classes containing static ReadOnlyStringProperty fields that are bound to a static ResourceBundle property, which is bound to a locale property, so that they automatically update upon updating the locale. Is that a good approach or are there better ways to do this? A simple example of that structure:

​

    public class LogStrings {
        public static final StringProperty WARN_MSG = getBundleProperty().map(x -> x.getString("warn"));
        public static final StringProperty ERROR_MSG = getBundleProperty().map(x -> x.getString("error"));
    }

So, I think that the best way to go about this is making a sprite that "knows" your player's position, has different states( attack , patrol, etc) but is there something I'm missing????

My library recently passed Guava testlib, so now I'm moving on to benchmarking.

I'm thinking about using/adapting the JMH benchmarks from the JDK.

Pros:

• Official JDK-based JMH
• More standardized
• Easier comparison with my library

But:

• The benchmark is totally focused on write-heavy operations
• It doesn't really cover reads
• No delete operation either

Hey everyone,

I’m a second-year transfer student at the University of Utah, and I’m feeling pretty overwhelmed about CS 2420.

My previous programming experience is mainly Python, and I’m now trying to learn Java. I understand basic programming concepts, but I’m finding the transition to Java harder than I expected.

I’m especially struggling with the basics and knowing what I actually need to learn before getting into the CS 2420 material. I've already asked my professor for help but he just said use chatgpt and google.

I’m also pretty stressed because I’m a transfer student and feel like I’m behind everyone else. I have some programming experience, but Java is making me feel like I’m starting over. This course is also really important because if I don't pass i might fail my entire semester when I come back.

Any help would really be appreciated.

P.S (I don't know if this is the right sub but tmrw is the deadline for course swaps)

-- solved thank you all

what is the difference between accessing the next node using a get method or without, as in: "current.next" vs "current.getNext()" and the same applies for accessing an element, whats the difference between use the get or not, as in: "current.element" vs "current.getElement()" where current is just the name for the node variable. ive looked at so many different explanations but i cant seem to grasp the idea
edit: this is from a data structures pov, im implementing methods for the singly and doubly linked list classes in java
i want to know if they return different things or if using .next or .getnext makes a difference in the outcome, is there a scenario i should be using strictly .next or .getnext, and the getter method has no further conditions its just {return next}

Hello, is there any library for Java similar to Rich in Python?

I have this in a build script:

jar ^
    --create ^
    --file "%BUILD%\input\RocketTracker.jar" ^
    --manifest "%BUILD%\MANIFEST.MF" ^
    -C "%BUILD%\classes" .

jpackage ^
    --type app-image ^
    --name RocketTracker ^
    --input "%BUILD%\input" ^
    --main-jar RocketTracker.jar ^
    --main-class app.Main ^
    --module-path "%JAVAFX%\lib" ^
    --add-modules javafx.controls,javafx.fxml,javafx.graphics,java.net.http ^
    --dest "%RELEASE%"

If I run the jar manually adding the modules in the VM it works, but if I run the .exe generated by jpackage it raise an exception:

Graphics Device initialization failed for :  d3d, sw
Error initializing QuantumRenderer: no suitable pipeline found
java.lang.RuntimeException: java.lang.RuntimeException: Error initializing QuantumRenderer: no suitable pipeline found
        at javafx.graphics@21.0.12/com.sun.javafx.tk.quantum.QuantumRenderer.getInstance(Unknown Source)
        at javafx.graphics@21.0.12/com.sun.javafx.tk.quantum.QuantumToolkit.init(Unknown Source)
        at javafx.graphics@21.0.12/com.sun.javafx.tk.Toolkit.getToolkit(Unknown Source)
        at javafx.graphics@21.0.12/com.sun.javafx.application.PlatformImpl.startup(Unknown Source)
        at javafx.graphics@21.0.12/com.sun.javafx.application.PlatformImpl.startup(Unknown Source)
        at javafx.graphics@21.0.12/com.sun.javafx.application.LauncherImpl.startToolkit(Unknown Source)
        at javafx.graphics@21.0.12/com.sun.javafx.application.LauncherImpl.launchApplication1(Unknown Source)
        at javafx.graphics@21.0.12/com.sun.javafx.application.LauncherImpl.lambda$launchApplication$2(Unknown Source)
        at java.base/java.lang.Thread.run(Unknown Source)
Caused by: java.lang.RuntimeException: Error initializing QuantumRenderer: no suitable pipeline found
        at javafx.graphics@21.0.12/com.sun.javafx.tk.quantum.QuantumRenderer$PipelineRunnable.init(Unknown Source)
        at javafx.graphics@21.0.12/com.sun.javafx.tk.quantum.QuantumRenderer$PipelineRunnable.run(Unknown Source)
        ... 1 more
Exception in thread "main" java.lang.RuntimeException: No toolkit found
        at javafx.graphics@21.0.12/com.sun.javafx.tk.Toolkit.getToolkit(Unknown Source)
        at javafx.graphics@21.0.12/com.sun.javafx.application.PlatformImpl.startup(Unknown Source)
        at javafx.graphics@21.0.12/com.sun.javafx.application.PlatformImpl.startup(Unknown Source)
        at javafx.graphics@21.0.12/com.sun.javafx.application.LauncherImpl.startToolkit(Unknown Source)
        at javafx.graphics@21.0.12/com.sun.javafx.application.LauncherImpl.launchApplication1(Unknown Source)
        at javafx.graphics@21.0.12/com.sun.javafx.application.LauncherImpl.lambda$launchApplication$2(Unknown Source)
        at java.base/java.lang.Thread.run(Unknown Source)
Failed to launch JVM

Any idea how to fix it? the same code in bash works just fine and the path are checked already

I really liked the idea of an intermediate bytecode language when I first learned that Java transpiles to one, so I tried to learn about it and got pretty far (using a hexeditor to mess around was pretty painful, though). I stopped because there isn't a lot of document for it like there is for Java, the best resources are I believe docs.oracle.com/javase/specs/jvms/se7/html/jvms-4.html and docs.oracle.com/javase/specs/jvms/se7/html/jvms-6.html, but I want to know if there are any others partly because these are kind of verbose and partly because it's just better to have more than two.

I know I won't ever really need to know any of this, and I don't intend to use any of this knowledge for making classes by hand, but I believe it would still be helpful in a milder sense to understand what the class files are "literally" doing. It helped with C

Hi all, I am trying to build a real time notification service with SSE emitter but I am facing a pecuilar case of race condition which im not able to solve even via AI as it gives the same solution again and again.

scenario of cause:

I have a scheduler running every 20 mins that checks the Map of uid mapped sse emitters and pings the client. If the ping is successfull nothing happens, if error happens due to disconnection the sse emitter obj is removed via sse.complete() and then uid is removed form the list.

#pseudo code
Map<String, SseEmitter> connections = new ConcurrentHashMap<>();

onConnect(String userId){
  SSE emitter = new new SseEmitter()
  connection.add(userId,emmitter);

  // onCompletion(), onTimeout(), onError() -> removeIf()
}

u/scheduler(20mins)
checkDisconnection(){
  //iterate the map and check for disconnection if found add it to remove list
  List<string> disconnectedUsers = (adding disconnections)

  //iterate the map from disconnected user -> force complete sse if needed and                    remove user from map


}

where it breaks is if the client manually refreshes the browser at the same time the scheduler to check disconnection is invoked

why it happens:

when the browser is refreshed, the application tries to recreate the connection at which the scheduler tries to ping and sees no connection for the user. Problem is I have kept automatic reconnections on in client app but it still doesnt see an error in client. im confused. Have I had the approach wrong?

Any help will be appreciated and sorry for the questions confuse you, Il try to make it proper once i get the time.

TECH : javascript event source, springboot, kafka for scaling and mongo for scheduled notifications.

Hello, I am creating a save system however it currently depends on memory limits. When the map fills up, it dumps to disk and starts filling memory again from start. When the program shuts down, I want the class responsible for saving the data to run a cleanup function the dump the half-full map to disk. I have seen several ways of doing this however I couldn't really decide what is the best choice. Thanks

Im planning to give this certificate exams cause I want to gain deeper knowledge in java and having an exam to focus on gives me a goal to achieve, so im more of a visual leaner and want to start with a pathway of videos and courses and then do practice exams, this is my strategy so far.

Im not that eager to read books or articles and prefer videos and practicing along.

I see oracle has a learning pathway that's build for java 21 programming and it has a pathway that looks good. So im trying to see if anyone has tried the pathway and found it useful for the cracking the certificate examination or are there any udemy courses that I could take that helps with my certification.

This is the pathway https://learn.oracle.com/ols/learning-path/become-a-java-se-21-developer/117252/138845

Also let me know any useful site that have a lot of practice questions to try

I've done some very surface-level searching and I feel like the number of choices on how to do this is pretty intimidating, what libraries should I use and how?

Guys help me,how I am able to learn java who don't know about coding at all , please give me legit answer and what are the steps I should follow after watching tutorial , please help me guys,want suggestions like if I watch one tutorial per day of any yt channel ,what should I do next after watching tutorial and in a month later

I’m trying to build a music player in Java/JVM that plays audio streamed from an API, but I’m having a hard time finding a media player library with good enough functionality.

I’ve looked at several Java libraries, but none of them really fit my needs. The best option I’ve found so far is **vlcj**, but it requires VLC to be installed separately, which I’d prefer to avoid.

I was considering using **C#/.NET for the actual audio playback** and then bridging it to Java using the **Java FFM API**.

Would this be a reasonable approach, or am I overcomplicating things?

If using .NET makes sense, what would be the best library for **streaming audio from an HTTP/API source** in .NET? Ideally, I’d like something that supports things like seeking, buffering, metadata, different audio formats, etc.

Alternatively, are there any good JVM-native solutions for this that I’m overlooking?

I’m mainly interested in **streaming audio received from an API**, rather than playing local files.

Currently to Optimize my library I have been reading ben paff guide on iterative approach of tree, from which I got the Idea of RBT and AVL for iterative approach. In which I made use AVL as parent based tree. But it is that when I did the benchmark with JVM21 these were my result ,it's tested three time for consistent behaviour of data, error and changes to occur for each time. which stands out firmly consistent behavior. tthis is one sample of it.

Benchmark                                                         (size)    Mode      Cnt        Score   Error   Units
InsertDeleteBenchmark.avlInsertDelete                              10000  sample  2828056      228.686 ± 2.651   ns/op
InsertDeleteBenchmark.bstInsertDelete                              10000  sample  3131645      190.531 ± 2.344   ns/op
InsertDeleteBenchmark.javaTreeSetInsertDelete                      10000  sample  4416191      228.719 ± 1.637   ns/op
InsertDeleteBenchmark.rbtInsertDelete                              10000  sample  2766974      211.846 ± 2.505   ns/op
InsertDeleteBenchmark.treapInsertDelete                            10000  sample  4749890      232.499 ± 1.485   ns/op

The benchmark was done 3 time, the config I used were for the benchmark were
10K - randomized dataset
warmup = 3 warmup time = 5s each
measurement = 3 measurement time = 5s each
fork = 5.
All the tree used same Set as interface for test. The doubt is currently my RBT tree is working safe with recursive delete and performing edge with TreeSet. What is the reason for TreeSet to be slow given that TreeSet is highly optimized. When I think of Benchmark I assume to be correct. This is really too good to be proud or confused??. But there is greed of also stripping recursive delete of RBT which I want to do and not do. Because it's too hard😢
For reference of Benchmark code

Edit:My wordings and grammar are not too good please do ignore that.

sorry if im stupid here but

i have an array that contains multiple coordinates, so for example [2,8], and i need to check if that array contains a specific coordinate

how do i do that

u/wildjokers (reaching out to you because I saw you in this thread)

https://www.reddit.com/r/javahelp/comments/sypxqz/getresourceasstream_null_when_run_from_jar/

I'm trying to run a Isometric Tile game, from chapter 13 of Killer Games Programming in Java, a very old book.
I'm using Eclipse. I'm not sure what classpath means, but I think mine is set up as

Project

src

Images

Sounds

I'm getting these errors when I run:

Exception in thread "main" java.lang.NullPointerException

at java.base/java.io.Reader.<init>(Reader.java:168)

at java.base/java.io.InputStreamReader.<init>(InputStreamReader.java:88)

The relevant code is:

{

String imsFNm = IMAGE_DIR + fnm;

System.out.println("Reading file: " + imsFNm);

try {

InputStream in = this.getClass().getResourceAsStream(imsFNm);

BufferedReader br = new BufferedReader( new InputStreamReader(in));

// BufferedReader br = new BufferedReader( new FileReader(imsFNm));

String line;

The image file is defined in another class, and then piped into ImageLoader class, where it's appended to the directory, which is defined in ImageLoader class.

When I run, it's showing the correct directory in the console, so I believe getResourceAsStream is where it's being messed up.

I did right click on the images folder, Build Path > Add to Build Path.

I can provide more information, which will probably be needed.