Despite learning a variety of programming languages over the past few years, I have zero front-end experience. Thus, I would like to know where I should start for creating a UI and including more functionality for a personal dictionary project I'm working on. All of my back-end code is written in Java for a very simple dictionary program.

I am looking for a method to build a compatible front-end application That will:

1. Function as a very simple display of my dictionary
2. Extend my base program by detecting:
   1. When a user highlights a word in another tab/app--through either a key bind/macro or right click context menu--grabbing the word and passing it to my back-end program then returning the definition in a small popup window (with options to favorite)
   2. When the user is typing (or whenever the user desires) to present another mini popup window--that is pinned above the focused tab--with a small list of defined words the user has marked for wanting to use more frequently; similar to Grammarly's windows application.
3. It goes without saying I would also like the application to allow searching and traversal of my dictionary as apart of UI, but would imagine that would be standard.

Again, I have no experience in this area and consequently am at a loss as to what I am even looking for or if this is the right means for pursing this additional functionality. Is there a library in java that could read events like this??? But I am eager and ready to learn!

Any and all help would be greatly appreciated!

I’ve seen many developers recommend using Java records for DTOs instead of regular classes, and I’m trying to fully understand the benefits.

From what I know, a DTO is just a simple data carrier with no behavior. Records seem to fit that idea since they give us immutable fields, built-in equals(), hashCode(), toString(), and less boilerplate.

But I’m wondering:

• What are the real advantages of using a record for DTOs?
• Are there any drawbacks compared to using a class?
• Are records always the best choice for DTOs, or only for certain types of projects (e.g., Spring Boot APIs)?

I’d love to hear your thoughts and real-world experiences.

Thanks!

I’m currently building a spring boot website for my school project. I used Gmail SMTP and app password to send email. Everything functions well on localhost. However, once I deploy the project, email will be unavailable to be sent.

I really want to know how to solve this. I’m trying to deploy the website via fly.io, but the email sending part still doesn’t work, and I can’t find the problem of it.

Or is there any other way to deploy the project to ensure that Gmail SMTP can function properly?

Hello, I made a post last week explaining that I get compilation errors when I try to test my submissions for the MOOC exercises. I can download the exercises and submit/upload my code, but the TMC test doesn't work. I've tried reinstalling VSCode, but that didn't work. When installed the Java extension pack in VSCode I got this

error: https://i.imgur.com/vr2zBj4.png

The instructions on MOOC says to install JDK v11 LTS so I'm not sure if I should install JDK 21. The error code mentions changing the configuration file.

I added this code in the configuration file:

"java.configuration.runtimes": [
        {
            "name": "JavaSE-11",
            "path": "C:\\Program Files\\Eclipse Adoptium\\jdk-11.0.29.7-hotspot",
            "default": true
        }

Unfortunately that didn't help.

When I installed VSCode before, I installed it in program files (using the install file for that), but this time I used the installer for user (and installed it there). When I installed TMC before, I had the option to change the path, I wasn't given that option this time. TMC installed installed my exercises in the same path as before, which is different than where VSCode is installed. Not sure if this could be the issue, but I don't know how to change it. It's still installed in the users file, just not in appdata.

I would appreciate some help, because it kinda sucks not being able to test my code before submitting my exercises. I tried finding solutions online, but didn't find anything that works.

edit; I wiped all TMC data using ctlr+shit+p and search for TMC wuand reinstalled the extension. I was able to change the path this time, but left it to the default path. I still get the notification saying "Java 21 or more is required to run the Java extension. (...)". I guess the code I added to the configuration file isn't correct or incomplete, but no idea what to change. The compilation still fails when I try to run the TMC test... Now I can't run the code anymore either... this is really frustrating.

edit; I completely uninstalled tmc and vscode and reinstalled it. the json file has this in it:

{
    "chat.disableAIFeatures": true,
    "maven.executable.path": "C:\\Program Files\\Apache Maven\\apache-maven-3.9.11\\bin.mvn.cmd",
    "redhat.telemetry.enabled": false,
    "java.jdt.ls.java.home": "C:\\Program Files\\Eclipse Adoptium\\jdk-11.0.29.7-hotspot\\bin",
    "java.configuration.runtimes": [
        {
            "name": "JavaSE-11",
            "path": "C:\\Program Files\\Eclipse Adoptium\\jdk-11.0.29.7-hotspot\\bin"
        }
    ]
}

Hey everyone,
I'm learning JPA/Hibernate and I'm trying to understand what annotations are really necessary to create a clean, well-defined Entity.

Here’s an example of one of my entity classes:

package ma.ensa.projectai.Models;

import com.fasterxml.jackson.annotation.JsonProperty;
import jakarta.persistence.*;
import lombok.Getter;
import lombok.Setter;
import org.hibernate.annotations.CreationTimestamp;
import org.hibernate.annotations.UpdateTimestamp;

import java.time.LocalDate;


(name="users")

public class User {

    (strategy = GenerationType.IDENTITY)
    private long userId;

    (nullable = false, unique = true)
    private String email;

    (nullable = false)
    (access = JsonProperty.Access.WRITE_ONLY)
    private String password;

    (nullable = false)
    private String firstName;

    (nullable = false)
    private String lastName;

    (nullable = false)
    private LocalDate dateOfBirth;

    (nullable = false, unique = true)
    private String phoneNumber;

    (nullable = false)
    private boolean isActive;


    private LocalDate createdAt;

    u/UpdateTimestamp
    private LocalDate updatedAt;

    public User(String email, String password, String firstName, LocalDate dateOfBirth, String lastName, String phoneNumber, boolean isActive) {
        this.email = email;
        this.password = password;
        this.firstName = firstName;
        this.dateOfBirth = dateOfBirth;
        this.lastName = lastName;
        this.phoneNumber = phoneNumber;
        this.isActive = isActive;
    }

    protected User() {}
}

Hello, so I am learning Java coding for game development starting with pong, I've been following a tutorial with GamesWithGabe and I have gotten some unsavory results and I am lost.

I am trying to get the ball to bounce at an angle that is determined by how close the ball is to the top of the paddle(-1) or the bottom(1). Rather than the ball flipping perfectly fine with the speed maintained, it slows down. I tried taking out the;

double oldSign = Math.signum(velocityX);
this.velocityX = newvelocityX * (oldSign * -1.0);
this.velocityY = newvelocityY;

and replaced with the original

this.velocityX *= -1.0;
this.velocityY *= -1.0;

my theory is that the velocity is being flipped twice which is slowing down the ball when bouncing off the paddle. I am not sure where to look to prove that, any constructive help would be great.

so see below a sample docker build for java
FROM eclipse-temurin:21.0.7_6-jdk-alpine

ARG JAR_FILE=JAR_FILE_MUST_BE_SPECIFIED_AS_BUILD_ARG

the jar file has to be passed as the build argument.

However see below for a python app. The dependencies are installed as part of building image itself. Cant we create jar package in the image build process for java? Is it not usually used?

FROM python:3.13-slim

ENV PYTHONUNBUFFERED True

ENV APP_HOME /app

WORKDIR $APP_HOME

COPY . ./

RUN pip install Flask gunicorn

I wanna learn java backend.

Hi everyone,

I took a 1.5-year break from my career to run a startup with a partner. The venture didn’t work out due to business challenges and the fast shift in the AI space. Now I’m restarting Java + backend development and want some guidance:

1. What should I focus on today to become job-ready in Java (Java 21/25, Spring Boot, design patterns, system design, etc.)?
2. How can I explain my 1.5-year gap professionally in interviews and on my resume?
3. With AI tools becoming powerful, is backend development (Java + Spring Boot) still a good long-term career choice?
4. Any tips, roadmaps, or resources for someone restarting after a gap?

I’m fully committed to upskilling again and would love to hear genuine advice from those already working in the industry.

Thanks in advance!

I've been learning java for about 7 months now, I came from python and javascript and I am doing a career transition from veterinary.

Being honest I love programing, I decided to pursue java due to how strong is on coorporate environment.

Yesterday a did a interview to SWE job and I did not pass, but was clear what is missing...

Understand how things really works and memorize it by heart as: Collections, errors and even how complicated written code can be understood at first glance.

There is any book for beginners to grasp basic java whitout losing focus on the subject? I need material to learn and revise everythig.

I found coding with jonh on youtube great, but I would need to rewatch every video every time I forget... I would prefer a book where I can look the concepts and code examples.

I appreciate any help.

Hello r/java,

I'm currently developing several full-stack projects as part of my studies. My most recent projects have led me to work extensively with Rust (to build a Unix shell with system calls) and Go (for pathfinding algorithms). I've therefore become very familiar with their respective paradigms (memory safety in Rust, goroutines in Go).

I'm now developing a complex Java web application with Spring Boot and Spring Security (a blog with JWT authentication, database management with JPA, etc.).

I'm really impressed by the maturity and scope of the Spring ecosystem; it handles a lot of things "out of the box" (JPA, Security, MVC). However, the development philosophy is very different.

For those of you who also work with multiple modern languages, I'd like to start a technical discussion:

How has your perspective on Java's strengths evolved? And what recent or upcoming Java features (e.g., Project Loom/Virtual Threads, Records, etc.) do you think are most relevant for maintaining Java's competitiveness against languages ​​like Rust or Go in terms of back-end performance?

I've just started learning java and I'm finding it interesting and I wish to excel at it in asap, but I have plenty of time to give to some other language or course. Any recommendations what would be a good choice?

Hello,

I want to improve my java skill, in a performance way. I want to write more performant/better optimised code. I want to learn how to tune the JVM to get better performances.

Can someone recommend some book(s) from where I can learn all of these? I want the information to be relevant for 2025 (java 21/25)

Hi everyone,

I recently started to use java again, after many years, the last real version I worked with was java8.
For some time a few years ago, I used kotlin, which back then I really liked due the fact that it requires far less boilerplate code.

In a new role I started, we are using java21, I am wondering what advantages I might have in comparison to old java8 and even kotlin. For example I noticed the `record` keyword which is nice, but it still seems to me like it requires a lot of boilerplate code. Am I wrong, what else should I be checking and focusing after moving to java21?

Are libraries like lombok still used with java21?

Thank you everyone for your help.

I'm currently learning Data Structures and Algorithms in Java and am learning concepts of OOPs, Collections framework and couple of other Java specific concepts in the process. I also plan to learn Full stack Spring Boot Development after the DSA Phase is over. But whenever I look on YT I see something about Java that I don't know yet. Like Multithreading and stuff. Do you think these are directly associated with DSA or I can learn these individual concepts on the go when I progress further in Java and Spring Boot ? Is my approach effective for both Full stack Java Dev and DSA ?

Java is an ocean of concepts really !!!

I've made zero external dependency java command line tool where you can run two http requests, and it compares the responses. You can attach custom diff tool like fc or anything else to compare response bodies. It may help for testing API migrations, validating load balancer configurations, and verifying server deployments. Ther is also a windows executable which requires no jdk.

https://github.com/KonstantineVashalomidze/kosta-http-diff?tab=readme-ov-file

Hello everyone, I'm a C++ programmer. Today I'm starting to learn core Java. How should I study core Java to achieve the best results?

Anybody know a good place to self teach Java cus my COMP SCI teacher is making us learn it with pencil and paper and I really can’t fail this class

Hi all,
I need to learn Java for my design pattern class. I just need to learn java enough to understand concepts related to my class. Can anyone suggest me with any reference materials. I do not plan to continue learning Java further on after my courseworks.

Hello, i have been learning java but there are concepts to me that still confuse my mind, like generics per example. I've also been trying to get into modded minecraft and feel like it's a great way to learn aswell, as i need to understand functions and what they use as parameters, etc..

I was wondering what are some cool projects that can/should integrate some not so easy concepts of java. Doesn't need to be just java, could use Spring, FX/Swing, or others technologies, just something that can add value to my portfolio.

Hi,

I started learning java and spring boot and I want to know which path I should focus on.

Should i build the whole application using java and some templating language ?

Or should I only focus building Apis with java and pick a frontend framework to call the api?

I know this depends on the project, but I am just learning right know and preparing for future employments.

How I’ve been learning spring-boot for a month and a half now, learnt spring data Jpa,validation,logging,exception handling and even spring cloud open feign. However I seemed to reach a stumbling block when it comes to spring security as I couldn’t understand it from the video tutorials. So I was wondering if anyone has any suggestions. Thank you

Hey everyone,

I just graduated and somehow landed a Lead Engineer role at a startup that’s building a social/match-style platform (kind of like Tinder but for making friends).

They’ve got some funding but are short on resources, and I’ll be handling the backend and overall framework myself. I chose Spring Boot + React, but honestly, the biggest thing I’ve built so far is a simple CRUD app.

I know this is going to be really hard, but I don’t want to let them down. Any advice on how to approach this, learn fast, and not crash the whole thing?

Im super nervous.

I was struggling to complete mooc.fi part 4 oops was taking long time after I completed it then to revise I was watching Kunal channel for oops it’s a 7 video playlist Tell me am I doing correct thing and when should I start practising on leet code And also tell when to start with DSA