Switching Enviroments

I'm a apprentice and have done my first year of this apprenticeship. I started in August 2024 and now its the end of my first year. After the summer holidays, I'll be working in the company. I've been told that they use Eclipse, and we work with Swing. In the first year I learned how to code in Java a little bit. I learned what objects, classes, instances are. Just the like most basic stuff. I don't know if it is considered basics because on how easy it is. What I also learned is how to use JavaFx with SceneBuilder. I made a project management system with it and it had all sorts of stuff. Excel Exporter and everything. I learned pretty well and after that I didn't touch Java a single bit since we are learning other Stuff too.

What I currently know in Java without using anything is how to create classes, objects and instancing. That are things i can do without looking anything up.

Now I'm switching to Eclipse and i did a full factory reset on my computer to have everything cleanly organized.

What i currently have installed:
- Eclipse IDE 2025-06
- JDK 21
- Everything (from voidtools)
- Obsidian
- DevToys
- Git

My boss said that I don't need to install plugins because Eclipse has many built in features.
Is there something I should install or do?
What should I learn during summer holiday? (4 weeks)
Which Documentations should I read?

Thank you in advance

Welcome to the Ranch,  Vijiyarathan!

Eclipse is virtually nothing but plugins. However, if you install the enterprise java spin, most of the plugins that you need for desktop and web-based Java developments will be pre-installed. With the possible exception of a plugin for WYSIWYG Swing design.

As far as what to study, I suppose that you'll have to determine that based on what you feel you might need most but understand least.

If you expect to develop Swing apps, study that. JavaFX is similar in some ways to Swing, but they're not interchangeable.

I'd take a stab at some Swing exercises.

And have you tried any typical beginners' excercises?
For example:
- Hello World.
- Compute first 100 prime numbers.
- Compute Euler's number.
- Order some array using Bubble sort.

I've done Hello World and compute first 100 prime numbers.

The Euler's number is e = 1 + 1/1 + 1/(1*2) + 1/(1*2*3) + 1/(1*2*3*4) + ...
If you want to play, you can use the BigDecimal class and compute 100 decimal digits of e.

Vijiyarathan Rithush wrote:I've done Hello World and compute first 100 prime numbers.

Please show us your HelloWorld, and tell us how you computed those prime numbers.

For general java exercises go to hackerrank.com.

In Swing
* Get to know Layout Managers
* Tables

Once you have a general grasp of layout managers tussle with the GridBagLayout but you'll want to use the GBC helper class which is floating around the internet or I can post you one if you need it.

I think there are improvements I could make.
I could've done it without an ArrayList and it would be way easier.
But I wanted to implement it since we basically only learned with ArrayList





Hoping for suggestions on Improving.

Suggestions:
Replace the while statement with a for statement:

Remove statements:  5 and 14
This restricts the scope of num and cleans up its usage.

Replace for loop starting  on line 17:

If you want an interesting exercise look up computing primes with  the Sieve of Eratosthenes. Extremely fast. You could even incorporate a "BitSet" object when writing the code.

Thanks for the advice and tipps.

I have a small problem with Eclipse. I don't know if its the same for everyone but when I type in the { then i dont get the closing bracket even if i turned it on.

In the prime numbers example you test whether the number can be divided by all numbers.
It would be faster to use only already computed prime numbers.

And another suggestion: In this test you evaluate the square root in every iteration.
I would do it only once.

You can program Hello World using JFrame.

Vijiyarathan Rithush wrote:... but when I type in the { then i dont get the closing bracket even if i turned it on.

Try to press Enter. I do not know if it helps, I have it turned off.

Petr Šlechta wrote:And another suggestion: In this test you evaluate the square root in every iteration.
I would do it only once.

Init looks like sqrt is calculated every time through the loop but the compiler is smart enough to call sqrt only once.

Hmm, I am trying to test if it is faster when I change the cycle to:And it seems the speed is the same.

Edit: I looked at the byte code and it is not optimized. But the virtual machine may make other optimizations.

You're  right. I guess it's left up to the  JIT compiler to do that optimization. So, it's a safer bet to write it the way you suggest.