I am a java beginner, the first java IDE I downloaded was Visual Studio Code, it was very easy to use and everything is auto configured. But it kind overheats my laptop all the time, so I want to try IDEA, so far it's a very good experience, except when I open a java file and tried to run it in IDEA, it always pops out this run configuration window and I don't understand how to configure it. In visual Studio Code I can open any java file any time and run without any issues, but now I have to go through creating projects every time. Is there any solution for this?
From how the file icon looks:
your file is not recognized as the part of the sources of your project. Check the project settings to ensure that source directories are correctly set.
I'd also recommend you to look up and follow the conventions for the directory structure of java projects.
Once you've fixed the problem with sources, you'll see "run" icon next to your class, main method, or when you're right clicking the file.
Command-line
To run a single file, there is no need for an IDE.
In Java 11 and later, the java tool at the command-line can both compile and execute a single-file Java class. See JEP 330: Launch Single-File Source-Code Programs.
If your class named HelloWorld were in a file named HelloWorld.java, on a console type:
java HelloWorld.java
To be clear: The java command-line tool really only executes Java apps, while the javac command-line tool compiles Java source code. As a convenience, the java tool was enhanced to effectively call javac on your behalf for a single-file.
JShell
If you just want to run a few lines of Java, try JShell, the REPL tool bundled with Java 9 and later.
See:
Java Shell User’s Guide by Oracle
JEP 222: jshell: The Java Shell (Read-Eval-Print Loop)
Search to learn more and find tutorials.
BlueJ
Using an IDE such as IntelliJ, NetBeans, or Eclipse can be a daunting task for the new student of Java. Those IDEs are heavy-duty tools designed for professional programmers.
I recommend using an IDE designed for beginners. BlueJ comes to mind, designed specifically for educational purposes. BlueJ makes getting started with Java easier.
If you insist on using IntelliJ, read on.
If using IntelliJ, define a project
IntelliJ is not designed to work with single files. IntelliJ expects you to work within a project.
I strongly recommend learning the basics of Maven to create and drive your new project. By defining your project in Maven, the configuration is independent of any one IDE. You can move your project between major IDEs such as IntelliJ, NetBeans, and Eclipse.
Maven is also very useful for downloading needed libraries ("dependencies") that you may want to leverage in your work. And Maven is good at packaging your Java app as a JAR (or WAR or EAR).
In IntelliJ, choose "New Project". In the New Project window, click the Maven item on left. Check the Create from archetype box. Scroll the list to find item for org.apache.maven.archetypes:maven-archetype-quickstart. Under that, choose the "RELEASE" item. Click Next button.
In Name field, enter something like MyFirstProject. Click Next button.
On the Maven settings page, just click Finish.
Wait a moment for IntelliJ to download some stuff and configure your project. Eventually you should see a BUILD SUCCESS message in the Run pane.
You will also see a pom.xml file displayed. The POM contains your settings for Maven to run your project, in XML format.
Change the <maven.compiler.source> and <maven.compiler.target> elements to the version of Java you are using. The current version is Java 17.
After editing the pom.xml, look for a little floating windoid with a tiny Maven icon. Click the icon to have Maven process your changed POM. Wait a moment.
In the Project pane, navigate to the App file. There you see code to print “Hello World!”. Let's run that code now. Click the green triangle button on the left, in the gutter, next to the main method line. A pop-up menu appears offering a Run item. Choose that item to run the app immediately.
Down in the Run pane, you should see the results, the Hello World! text.
At this point you can add your single file to the org.example package seen in the Project pane.
By the way, you can change that package name by context-clicking and choosing Refactor > Rename….
Later, learn to use the Run/debug configurations feature of IntelliJ.
Know that you need not create a new project for each time you want to do a little experiment. Create one project for such experiments. Keep adding new .java class files for each experiment. Delete old class files you no longer need.
Eventually, I suggest updating the versions of various items in your POM. The QuickStart archetype is not configured for the latest versions (for reasons I cannot fathom).
And when you learn about unit testing, replace JUnit 4 in the POM with JUnit Jupiter (Aggregator) to use JUnit 5. One of the benefits of using Maven is that you can easily switch out dependencies such as going from JUnit 4 to JUnit 5.
The IDE needs to know what's called the entry point of the program, i.e. where to start running your code. That's what the "Edit Configuration" window is wanting you to do.
If your file "Lab3.java" is in a package, make sure to fully specify that in the field you have in red. Otherwise without knowing how your project is structured (as the other answer alludes to), it's difficult to pinpoint what we're missing here.
When you create your IntelliJ project, add a directory /src right at the root of your project. Right click on that folder and tell IntelliJ that you wish to mark it as a source root. The directory should turn blue in color.
Put your packages under /src. IntelliJ will know that those are Java files.
When you want to run a class with a main method, choose Run->Edit Configurations. Tell IntelliJ that you want to add an Application. It should prompt you with the classes that have main methods in them. You'll have no trouble running them.
Use Maven or Graddle. Make sure the project is configured with the build tool enabled and integrated, it will do basic things automatically. If you are not sure, please create a new project and add your files in. Steps:
Open the IDE
New Project
Choose from the left side bar "Maven" or "Graddle"
Give it a name and the location in your machine.
Click Finish
Now you have the project ready. You need the appropriate method to run in java. A main class. In IntelliJ you can just type "main" and the auto-complete will add it for you, make sure you inside the curly brackets of the class {}. More info about the main class. You seem to have this nailed down.
Lastly make sure you have a JDK installed in the IDE. I am pretty sure this is your issue here, make sure to use one of the option IntelliJ provides. A full guide from the developers is here and should satisfy your needs. I would suggest OpenJDK for a beginner, because that served me well at the beginning, at the end of the day its your choice.
Recently we tried to include code analyzing tool in our Java builds - FindBugs.
But for some reason, after teamcity build finished and FB xml files parsed there is no Code Inspection tab on build page.
There is no errors in logs and i can't find a way to make this tab appear in a forced manner.
Apparently, Code Inspection tab appeared after TeamCity reboot and checking FB in bugged targets. So, tab may not be visible if there is no bugs (and sometimes you need to restart TC).
I’d like to ask for help. I installed the plugin and successfully added the SonarQube server. I upgraded to version 4.1.2. I use IntelliJ IDEA 13.0.2.
I also successfully associated the project and inspection warnings appeared. But when I fix the issue the status is not updated.
How to synchronize ?
I also run inspection by name ‘SonarQube issues’.
Nevertheless after running the inspection the warnings are also there, where the code was fixed. It seems to me the synchronization somehow fails.
Any idea, what todo, please?
What I had done in my situation.
Installed SonarQube 4.4.
Installed IntelliJ 13.1.4b (the same history was with 13.0.4).
Configured SonarQube intelliJ plugin (not community provided one but plugin from SonarSource). All instructions are under the link on Wiki.
Attached to Sonar project. Every step just as SonarSource recommends.
This gave me mapping from Sonar onto source code. But it does not update when I simply fix the issue. But if I fix issues I then re-post project onto Sonar through mvn sonar:sonar and this gives me updated picture next time I run inspection through sonarqube plugin.
But this is not 100% what is wanted. But definitely better than nothing. Also I have imported Sonar rules through QAPlug - this is far less useful. But notable faster.
Overall this configuration allows me to make what is needed but I'd like to receive real incremental processing without publishing local changes onto Sonar server.
Give a try to the SonarQube IntelliJ Community Plugin, it is made for fixing issues detected by jenkins on the local dev machine. Different then the official plugin you will need to do more configuration by yourself, but it gives you also the freedom to specify your local analysis script like you need.
What you need to do:
configure the plugin
setup sonar server
setup local analysis script
Afterwards you can run SonarQube (new issues) inspection, this will run the script and show the results in the Intellij. If you are fixing issues, you can just rerun the inspection from inside the inspections results tool window. This will rerun the script and show new results.
see also: https://github.com/sonar-intellij-plugin/sonar-intellij-plugin
Actually in our project, we are planning to start developing code (with SONAR to analyze from beginning only) , So we are making use of sonar plugin in eclipse. We know how to analyze code by configuring project to SONARQUEBE and making use of maven build tool as well as using sonarrunner. Instead of building maven for every code changes and analysing , is there any way that prompts (as well as show error lines ) sonar to immediately analyze just after saving the java file ?
Help will be appreciated..... Thanks in advance
There is currently no way to tie an sonar analysis to a save action.
However, you do not need to run the maven based analysis. Assuming you use a recent version of SonarQube and SonarQube ide (4+ and 3.3), you can simply run the analysis using the shortcut (ALT-Ctrl-Q, by default).
Using incremental mode with SonarQube 4+, this is actually really fast, because it analyzes only the changed files as compared to the last successful SonarQube run.
Of course, you need make sure that your buildserver regularily runs your full SonarQube builds as well.
Having dealt with yet another stupid eclipse problem, I want to try to get the lightest, most minimal Eclipse installation as possible.
To be clear, I use eclipse for two things:
Editing Java
Debugging Java
Everything else I do through Emacs/Zsh (editing JSP/XML/JS, file management, SVN check-in, etc). I have not found any aspect of working in Eclipse to do these tasks to be efficient or even reliable, so I do not want plug-ins that relate to it.
From the eclipse.org site, this is the lightest install of eclipse that they have, and I don't want any of those things (Bugzilla, Mylyn, CVS xml_ui), and have actually had problems with each of them even though I do not use them.
So what is the minimal build I can get that will:
Ignore SVN metadata
Includes the full-featured editor (intellisense and type-finding)
Includes the full-featured debugger (standard Eclipse/JDK)
Does not have any extra plug-ins, platforms, or "integrations" with other platforms, specifically, I don't want to deal with plug-ins relating to:
Maven, JSP Validation, Javascript editing or validation, CVS or SVN, Mylyn, Spring or Hibernate "natures", app servers like a bundled Tomcat/GlassFish/etc, J2EE tools, or anything of the like.
I do primarily Spring/Hibernate/web-mvc apps, and have never dealt with an Eclipse plug-in that handles any of it gracefully, I can work effectively with my own toolset, but Eclipse extensions do nothing but get in the way.
I have worked with plain eclipse up to Ganymede, MyEclipse (up to 7.5), and the latest version of Spring-SourceTools, and find that they are all saddled with buggy useless plug-ins (though the combination is always different).
Switching to NetBeans/Intellij is not an option, and my teammates work with SVN-controlled .class/.project files, so it pretty much has to be Eclipse.
Does anyone have any good advice on how I can save a few grey hairs?
You can download the empty Eclipse platform and then manually install the JDT tools.
Go to the The Eclipse Project Downloads page.
Choose the bundle you want, probably Latest Release.
On the download page of the chosen bundle:
Download Platform Runtime Binary
Download JDT Runtime Binary
Extract the Platform Runtime Binary archive file and run it (for example, by double clicking on eclipse.exe).
Install the JDT binary:
Click Help → Install New Software → Add... → Archive.
Choose the JDT zip file you downloaded.
Uncheck Group Items by category.
Select the Eclipse Java Development Tools.
Click next to install and restart Eclipse when prompted.
JDT from the Eclipse update site
You can also install JDT from the Eclipse update site, instead of downloading the binary.
To do this, do this following:
Skip downloading the JDT Runtime Binary, only download, extract and run the Platform Runtime Binary.
Go to the Install New Software, but instead of Archive chose the Eclipse download site.
Search and install Eclipse Java Development Tools.
The "Eclipse IDE for Java Developers" version isn't the smallest one! Look for "Eclipse Classic" - it doesn't contain most of the things you mentioned. It's larger in download size only, because it comes with source code.
See this comparison: http://www.eclipse.org/downloads/compare.php
You can use a thirdparty distribution builder like Yoxos and download just what you want.
A bit late to this party, but I asked myself the same question for a while, and while now I'm back to a more fully-fledged Eclipse installation, I used to to the following to streamline it a bit. Hope it helps.
What I Needed
Functionalities:
Java Support
Java + Java EE (XML) + Debug Perspectives
Pretty much it. There's a lot of other things I like to use in Eclipse, but I needed to keep it down to the skinniest possible because I was in a 3GB environment where I also needed to run other servers in parallel, so I couldn't afford much.
Resulting Perspectives:
Lightweight Java
Lightweight Browser (fairly tweaked for code reviews and code inspection - that one was actually heavier than the others)
Lightweight Debug
What I Did
Install Eclipse Java EE (install classic if not caring about the Java EE/XML bits)
disable hungry views
disable outline (when you need one, just do CTRL+O)
disable call and type hierarchies
disable decorators
disable menu entries (right-
disable toolbar items
even better: hide the toolbar
disable hovers and actions associated with that
disable spell-checking
disable XML validation
disable Mylyn
disable non-needed search forms in CTRL+H dialog (I usually actually only use the "File Search" mode, sometimes the "Java" one)
disable usage reporting
disable unnecessary plugins or features
disables perspectives and plugins loaded automatically on startup
restrict internal limits:
some views have a scope (enclosing class, project, working set, workspace...)
some views and UI elements have boundaries (console/loggers, highlighters, markers...)
tweak the eclipse.ini to:
-clean the workspace (slower, but I tend to prefer to do that)
use G1GC
reduce memory usage (I noticed that I can perfectly live with -xss128k and -xmx384 with G1, for instance. YMMV, of course, as always with JVM tuning.)
use a server VM (and point directly to the VM's DLL)
Also disable views you don't need in the "Debug" and "Code Browsing" perspectives.
Sorry, I had actually saved all of these as a set of 3 lightweight perspectives to re-import everytime on my new project, but I cannot get my hands on them at the moment. If I ever find then, I'll add a link to them here.
Instead of going for a ready package from Eclipse Downloads, from the same page go for the Eclipse Installer. Currently available for Mac, Windows & the beloved Linux. Launch the Installer which should update (or not if you are lucky enough :) ). Select "Eclipse Platform" which is the absolute minimum from this IDE, set your other installation preferences and install.
After the download/installation process, I'd suggest your head to Help->Install New Software and search for the Eclipse Marketplace (Yes, even that is not included in this package) just to make your life a bit easier.
Get as minimal an installation as you can, and then remove whatever is left that you don't want.
Longer answer:
I played around a bit. Here's how I experimented:
Extract a clean eclipse*.zip to two different directories; call it eclipse and eclipse-bak. We'll only modify eclipse.
Before starting it the first time, remove some of the features from the features folder. I got rid of org.eclipse.cvs, org.eclipse.epp.\*, ...mylyn\*, ...wst\*.
Start up Eclipse to a workspace. Create in that workspace a Java project, debugging configuration, etc. Stuff that you would want to do and that will complain if we remove the wrong thing. Open up the Error Log view.
Close Eclipse. Remove something (or a group of things) from the plugins folder.
Open Eclipse. Check the error log to see if something you care about couldn't load. If it did, add those things back from eclipse-bak/plugins. If not, close Eclipse and return to step 4 for a new set of plugins.
Using this I got my configuration to still be able to edit and debug Java files, but including only these plugins:
com.ibm.icu*
org.apache.*
org.eclipse.compare*
org.eclipse.core*
org.eclipse.debug*
org.eclipse.draw2d*
org.eclipse.ecf*
org.eclipse.epp.package.java*
org.eclipse.equinox*
org.eclipse.help*
org.eclipse.jdt*
org.eclipse.jface*
org.eclipse.ltk*
org.eclipse.osgi*
org.eclipse.platform*
org.eclipse.rcp*
org.eclipse.search*
org.eclipse.team.core
org.eclipse.team.ui
org.eclipse.text
org.eclipse.ui*
org.eclipse.update*
org.hamcrest*
org.sat4j*
Most of that is core stuff, but you might be able to trim it down further. Notably gone are Mylyn, the usage collector, EMF, CVS, WST, even JUnit (though I think you should keep JUnit).
I feel you man, when working with Eclipse, the application is constantly trying to help.
Ignoring workspace corruptions, I spend my development time fighting all the "helpful" things Eclipse does.
XML is not that hard to read, but it still confuses the shit out of me when I get the XML designer.
All it does for me is add an extra manual step to click on the source tab.
Every time a new version of eclipse comes out they redesign the front page and the distributions.
At which time a new quest starts for finding a way to debloat Eclipse again.
I have the same experience with extensions to Eclipse by third parties and avoid them if at all possible.
WTP has somewhat usefull stuff, but overall I prefer a basic java eclipse.
It is a good idea start with the Platform Runtime Binary and add JDT.
Manually extracting the JDT runtime doesn't seem to work for me these days, so it it better to use the update client.
You can use the marketplace client, but personally I have always found it rather annoying.
An alternative is to use the director. The director can install JDT without starting the GUI.
Here is a script that downloads eclipse Oxygen 4.7.3a and installs JDT unnattended:
#!/bin/sh
die() {
echo >&2 "$#"
exit 1
}
[ "$#" -eq 1 ] || die "exactly 1 argument required [INSTALL_DIR]"
[ -e "$1" ] && die "*warning* Aborting! location exists, eclipse already installed?"
INSTALL_DIR="$1"
TARBALL=eclipse-platform-4.7.3a-linux-gtk-x86_64.tar.gz
mkdir -p $INSTALL_DIR
if [ ! -f $TARBALL ]
then
wget http://mirror.csclub.uwaterloo.ca/eclipse/eclipse/downloads/drops4/R-4.7.3a-201803300640/$TARBALL
fi
tar -v -xf "$TARBALL" -C "$INSTALL_DIR" --strip 1
echo "\nUsing director to install java development tools, this may take a while..."
$INSTALL_DIR/eclipse -noSplash -application org.eclipse.equinox.p2.director -repository http://download.eclipse.org/eclipse/updates/4.7 -installIUs org.eclipse.jdt.feature.group
Simply call the script with one argument, the directory you want Eclipse installed.
Running the script gives me an unpacked install of roughly 129MB, which is more than 100MB smaller than the default download (zipped).
That is not to say you would not be able to shrink it further, but it should rid you of most of the crap.
The executable will be cached for future executions of the script, but it will still be slow, since it needs to go online to download JDT.
Unfortunately, I do not know of a way to cache the plugin download in a local folder.
You could of course zip the created installation, but the script is easier to commit to git.
This script will only work for new users as long as the mirror stays up and will need some updates when a new version is released.
But I am sure most developers are savvy enough to update the script if need be.
If you only want to use Eclipse for editing / Debugging Java I would suggest using a plain Text editor. It seems an overkill to install Eclipse and not use most of its features.
A very popular choice is VIM. Also check out this SO link for tips in using VIM as a Java editor. You can also debug Java code with a command line debugger as mentioned in this SO link.
I have figured out how to get the lightest possible eclipse with minimal efforts(imo). For the reference this is what I want in my eclipse:
Java project with Maven support
JavaEE support(Servers)
Debugging of Java application
(Irrespective of these you can install any feature that comes with Eclipse IDE with minimal effort, just follow the guide below)
Here's how I get it:
Go to eclipse download packages (Here's the link)
Find MORE DOWNLOADS (right hand side) and go to Other builds (Here's the link)
Now go to any build you like (Usually Latest Downloads -> whatever the first Build Name. Also There is links for older versions and archive site)
Under Platform Runtime Binary you can download Eclipse Platform as per your OS and/or requirement.
Now extract the archive and run the eclipse
Go to Help -> Install New Software...
Using Work with you can install your desired plugins and tools which usually ships with bulky eclipse
In Work with drop down select the site(mostly first) similar like this 2022-03 - https://download.eclipse.org/releases/2022-03 here 2022-03 is my eclipse version you may see different depending your version.
Now you can select the group(s) or expand the group(s) and select the specific plugins which you need and also you can filter by name like maven, debug, server, marketplace client etc in filter text input just below the Work with drop-down menu.
Install plugins and enjoy your very own lightweight eclipse.
Visual Studio Code
Fast forward to 2019 and we now can use Visual Studio Code with Java plugins. They provide a plugin pack to get you started with lightweight debugger and auto complete. Other plugins include maven integration, dependency viewer and more.
Visual Studio Code is a new(ish) editor/mini-ide from Microsoft which runs on Win/Max/Linux and has plugins for many languages.
Tutorial for setup: https://blog.usejournal.com/visual-studio-code-for-java-the-ultimate-guide-2019-8de7d2b59902
Edit 2019-06-21: MS now has a dedicated installer for Java integration with VS Code, including Spring Boot support as well. While the Intelisense is not 100%, it's vastly improved and now my go-to Java editor for testing and trying new things. Announcing the Visual Studio Code Installer for Java