How can I change the Projects Runtime Platform?
(standard NetBeans [8.1] Java Project [Java Application])
Details:
using Ubuntu with NetBeans 8.1
I have installed JDK 1.6, JDK 1.7 + JDK 1.8
My projects platform is Java 6.
My systems default Java is Java 7.
NetBeans-IDE was started with Java 8.
When I run the project via the IDE (Run project), the Project-Platform is used (which is Java 6).
I cannot change the Runtime Platform!
It's always: Project Platform
I tried to Manage Platforms..., but I still can't change the value of the Runtime Platform-ComboBox.
EDIT:
As I wrote in the comments, I don't want to change the Project-Platform.
The project should be compiled with Java 6 but run with Java 8 (when click on Run project).
What I want is:
Project-Platform = Java 6 (used to compile),
Runtime-Platform = Java 8 (used to run).
How can I change the Projects Runtime Platform?
Unfortunately you can't. As you point out, its value can only be Project Platform. Of course that invites the question "What is the point of even having that Runtime Platform field?".
I suspect that it may have been (unwisely) added to the GUI so that at some time in the future it will be possible to actually select a different JDK to run against. There is an open Bug Report for this: Bug 186747 - Can't Build and Run with Different Java Versions.
It's also worth noting that the Help documentation for the Run screen does not mention that Runtime Platform field. My own view is that the field should be removed until it serves a useful purpose.
What I want is: Project-Platform = Java 6 (used to compile),
Runtime-Platform = Java 8 (used to run).
Unfortunately that can't be done, as shown by the open bug. The best you can do right now is:
Create platforms for JDK 6 and JDK 8 in NetBeans.
Set the Java Platform to JDK 1.6 on the Libraries screen, and set the Source/Binary Format to JDK 6 on the Sources screen, then build to verify that no invalid APIs are being used.
Switch the Java Platform to 1.8 on the Libraries screen to run your 1.6 code under 1.8.
I realize that you don't want to do that, but unfortunately there's no silver bullet in the current release of NetBeans (8.2).
An alternative approach would be to build and run using only JDK 8, but include the Animal Sniffer Maven plugin "for checking projects against the signatures of an API", to verify that your 1.6 code was not using illegal APIs. But of course that's only viable for Maven projects.
Please look at Netbeans Project Setup - Setting the Target JDK in a Project
You just have to change the Runtime Platform at the Libraries option, that's all.
Just went through this pain for Apache NetBeans 14. I was trying to set a remote debug for a Raspberry Pi.
It works only if the jdk match on both the local and remote versions. In my case I set them both to 17.
I would have expected that the default jdk on the local machine should have been able to be changed but I fail to determine how.
I am running Ubuntu on the local machine so maybe the platform cannot be changed (don't know). Moving on.
Changed runtime platform
Related
I am a regular IntelliJ user, but most of my co-workers use Eclipse. A lot of them say the latest version of Eclipse "2020-09", which requires a JRE "higher than Java 8" in order to run, cannot be used to develop projects requiring JRE8.
This is pretty surprising to me, since I know it is possible to install multiple JDKs and JREs on one machine, I've done it plenty of times.
What is the typical way a person would configure Eclipse 2020-09 (already installed) to work on a project that requires a Java 8 JRE?
JRE 8 apps in eclipse workspace is possible by having the jre 8 jdk. It is true that in order to use eclipse 2020-09 you need java 11+ jdk/jre, but making projects that support jre 8 is still possible.Even I still use 2020-06 and before. Here is a method you could use to get JRE 8 implemented back in your project. Although you can change the defaults, this one will help you change the environment back to java 8 for 1 project.
Right click the library named somthing like "JRE system library[JavaSE-11]". Press properties. This is what you will see JRE System Library chooser image
Choose "Alternate JRE" then click "Installed JREs"Step Image
Press "Add" then you will see 3 options. Choose standard VM. Find your java 8 jdk directory. Usually it is something like C:\Program Files\Java\jdk1.8.0_251.
You can configure the default arguments for your jvm runtime. Then simply hit ok,select the jdk-8 library and close it. Then choose alternate jre again and in the drop-down choose jdk-1.8.0 or some name like that. This will only work if you also have java 8 installed alongside java 11 that is configured properly JDK
You can use Java 11 to start the Eclipse 2020-09 and configure a project to compile with Java 8. The problem is if you want a Eclipse plugin that uses CORBA for example. This module was removed from Java 11 earlier. In this case, I recommend to use Eclipse 2020-06.
Earlier versions of 2020-09 was working with Java 8. I had it, too. Then I updated and I got the same error message like you.
I propose to use an older one or to install JRE 11 and set the JAVA_HOME env variable to it.
The inside the IDE you can set java 8 like an JDK and develope your project with Java 8 while eclipse is running with 11.
I am trying to download Java 7 on my mac. All my professors require java code to be in Java 7. I have the dmg downloaded but when I double click the icon to install I get the error message :
A newer version of Java is already installed.
The only thing I can do is click close and it exits the install. How can I install Java 7 onto my machine?
If you are doing your "development" using an IDE like eclipse, there is a simple solution to your problem: within eclipse, you can change the "compatibility" mode for your projects.
Meaning - even when only Java8 is installed, you can instruct eclipse that your project should be using Java7 only. So when you write source code that uses Java8 features (like lambdas or such things); you will get compiler errors.
The only caveat: you still could be using classes/methods from the Java8 installation that don't exist in Java7.
I am using JDK8 on my normal desktop and I have a separate linux box that I am trying to run the Java program on.
The problem I'm running into is that the linux box is running jdk7, so the computer has JRE7 basically that it is running off of. My question is, is it possible to create a jar file in JDK8 that will be compatible with java 7?
I'm using IntelliJ to compile. I tried to compile in 1.7, but it gave an error when I did end up trying to do it. I compile it here:
In 1.8 it works fine to compile, but when I try to compile in 1.7 it doesn't work.
I know the short answer is to update the linux to JRE 8. But I am curious, is there a way to make it backwards compatible? Or is the other answer to simply install JDK7 on the desktop in order for it to run on the linux box using JRE7?
Java programs built with JDK 8 will only run on machines running JRE 8 (or higher).
I found this when trying to compile classes on my local Linux machine (using JDK 8) and deploying to a remote server running JRE 7. The classes just wouldn't work (like you're finding).
If you want to use JRE 8 on linux, I recommend using the oracle-java8-installer package from webupd8team. Installation instructions found here (assuming Debian based distro).
If you want to compile to JDK 7, it's not good enough to only have JDK 8 installed and pick to compile 1.7. You need JDK 7 installed to and restage your project to use JDK 7.
The thing you have to remember is that the difference between JRE/JDK versions is not just the extra features developers can use (e.g Lambda functions) but it's also that the JRE itself is improved (efficiency, garbage collection, etc.).
As a extreme example: If you wrote code that only used JDK 1 features but compiled it using JDK 8, it wouldn't run on a machine running JRE 1 because the Java classes had been compiled with JRE 8 in mind.
Do note though, that if you're Java Code uses only features from JDK 7 or 6 etc., you might think it good practice to compile using the minimum JDK required to allow for compatibility with more machines. Well...you'd have that compatibility but at a cost of using inefficient, out of date, possibly vulnerable compiled classes (At little extreme, but you get my point).
Are you using any new Java 8 features? Because if you are, this means you cannot build the project against the JRE7.
If you are not using any Java 8 features, you can build to Java 7 most easily by downloading the JDK7 and switching the project to use that instead of the JDK8.
You should also set project language level to 1.7 (and module language level(s) as well, if they're different). It's done in Project Structure settings dialog. After that the project should compile.
Note that you shouldn't use any of the APIs that appeared in 1.8, but such usages will most likely be highlighted in the editor.
As we know, we are in transition between Java 7 and Java 8. I have both Java 7 and Java 8 JDK installed. However in the interests of keeping a hands-off approach I want to make java 7 JDK my default Java build environment.
Leaving Java 8 JDK installed for trials, testing, and migration.
However at the current time, Netbeans 8 insists that Java 8 is-the default.
What I'd like to set: Java 7 is default.
And only specify Java 8 on a per-project basis until I'm satisfied with the new build. At that point, I imagine we would change our default Java. The challenge is that there's no clear way to change a default Java configuration.
This is not helped by the fact that the "Java Platform Manager"is not part of "Options", and lives on the Tools menu / "Java Platforms. I have been able to to this successfully with IDEAJ when moving from Java 6 to Java 7. Everyone is using Netbeans on this project so we need to achieve the same end with Netbeans. To be clear, I'm comfortable using Java 8 for the Netbeans runtime. It is just project builds that I want as a specific Java 7 target environment.
According to the topic below: In NetBeans how do I change the Default JDK?, changing NETBEANS_JDKHOME will also change my netbeans running environment. So I would prefer to just set the build-target generally. Thanks in advance!
see also:
In NetBeans how do I change the Default JDK?
Netbeans v8 README: "nbjdk.active [since 5.0u1] - name of a Java platform (JDK) to use when building and running".
If I understand you question properly, each project can be assigned it's own Java Platform property, for example, right click the project in question and select "Properties"...
From the properties dialog, select "Libraries" and then select the "Java Platform" you want to use...
Personally, I find having the platforms pre-configured simpler.
If you're upgrading a project, you may also need to check the "Source/Binary Format" property in the "Sources" sections (it's own the bottom), as it will stay at the level of the old version of Java (if you downgrade, it adjusts automatically)
One solution is to change the netbeans configuration file netbeans.conf with is located in ...\NetBeans 8.0\etc.
But it does not work well...
The bypass we found is to spefify the jdk in the shortcut that launch Netbeans into
"...\NetBeans 8.0\bin\netbeans.exe" --jdkhome "C:\Program Files (x86)\Java\jdk1.7.0_60"
I have developed a Java Application in Eclipse using JDK 1.7.0, the application runs and everything works as expected.
Now I would like to send the application to a colleague of mine who is using a different version of the JDK. He is using 1.6.x.
I am not interested in him opening up the application and debugging through it in Eclipse. I would only like him to run it. If I make a runnable .jar of the application and send that to him, would it work even though he has a different JDK installed on his machine?
Thank You.
You need to compile it using JDK 1.6 (or lower). Provided your code doesn't use features from Java 7, you won't have to change anything in your sources
It would work if your colleague had a newer JRE than the JDK you used to compile it. All versions of JRE are backwards-compatible with all class files built with previous versions, but the opposite can clearly not work because new versions introduce new features. Your colleague will get an UnsupportedClassVersionError.
However, it is easy to set up in Eclipse the target class version for your project: go to Project Properties, Java Compiler, and under JDK Compliance choose the version 1.6.
Needless to say, this will fail if your source code uses any features or library calls which the version 6 does not support.