all I have installed both JDK 1.7 update 21(1.7.0.210) and 51(1.7.0.510), and so I wonder do I need to uninstall the older version which is JDK 1.7 update 21, as they both show up in the list of Programs and Features on Windows. Second, I tried Java Uninstall Tool, it only reports There are no older versions of Java on your computer. So I wonder can I just use the Programs and Features that manually uninstall any version of Java if I need to.
Another question is that I am using Eclipse doing Java and Android programming, so I wonder if I remove the older version of Java, will it affect the compiler settings in Eclipse, since Eclipse is kinda automatically detects your JDK versions and hence sets Compiler compliance level in Preferences.
cheers
Related
I want to install Java on a few different servers for running a third party service on tomcat.
I am not a Java developer and I got a bit confused when I began searching for the installer.
I checked the different Java versions and their long term support dates.
It seems that Java 11 JDK is - LTS so i decided to use it.
But when I was trying to find a runtime version (JRE?) since this is the version I am supposed to install on the server(?) I only found Java JRE 8.X.X, and this got me confused.
There is no higher major version of the JRE?
How does it work if you use the JDK 11 or even 14-15 as a developer and then use Java 8 JRE on your deployed servers?
Maybe the JDK holds inside of it the Java 8 JRE version?
Or do you actually need to install the JDK version on the servers instead?
The JRE is a subset of JDK. It contains everything needet to run Java applications but no support for development. So, if you need a JRE, a JDK is also good, although it conatins much stuff that you will not need.
Normally, for executing a Java application, you need a JRE with the same version or higher than the JDK used for development. But the developer can advise the compiler to generate code for a lower version. If he does so, he cannot use the features of the higher versions. For example the compiler of JDK 1.8 can produce code for JRE 1.6. You should consult the manual, to see which old versions are supported by the compiler of a specific version.
After some research,
It seems there is no separate JRE section anymore.
Also JDK 11 for production is not free and I guess this is an ongoing trend for the near future.
On a side note there is the open JDK 11 version but it does warn you about outdated security updates.
So basically in my case sticking to updated Java JRE 8 version is good enough for the near future.
Does VS Code (code-runner extension) support JDK 1.8? In the morning I was using JDK 12 , but then I downgraded to JDK 1.8 to try out applet viewer and stuff. Unfortunately now it doesn't even highlight the code.
Someone please tell me the problem and its solution.
JDK 1.8 is supported by VSCode.
Read https://code.visualstudio.com/docs/languages/java and install needed extensions.
Update 2021
Currently to use the Java extension in VSCode its required JDK 11, but you can still use older versions of JDK in your projects. See this to get information about how to configure other JDK version for your project.
Java 1.8 was no longer supported since "Language support for Java" extension upgrade to 0.68.0, I downgraded to 0.64.1 which works for me.
As stated here:
Note: Although the Java language server requires JDK version 11 or above to run, this is NOT a requirement to your project's runtime.
This means that you need to have JDK 11 or higher installed. You can also install older JDKs and configure the runtimes. Just open the Command Palette (Ctrl+Shift+P) and type the command Java: Configure Java Runtime. If you have JDK 8 installed and have properly configured maven or gradle, this isn't even necessary. Visual Studio Code will correctly pick up the correct JDK.
VS Code no longer supports JDK 1.8. The "Java Extension Pack" relies upon "Language Support for Java(TM) by Red Hat" which documents Java 11 is the minimum requirement. See here: https://marketplace.visualstudio.com/items?itemName=redhat.java
Tis unfortunate, guess I'm switching back to eclipse
So basically, at school our machines have an older version of the Java JDK installed, and I want to work on a netbeans project on home. I have it set up through the github and wanted to know if switching between JDK versions will mess up my project at all, if the older version will allow me to even open the newer version. And, if I can't, was curious on how to open a project in an older version of the JDK.
Thanks!
You just simply need to not use language features introduced after the version your school uses. Netbeans will give you hints if you attempt to use something when the version doesn't support it however (e.g. Diamond operators in 6, or using Lambdas when not using Java 8). So overall I would say you shouldn't be running into any issues, you can even make netbeans recognize the sources as an older version of Java by right clicking your project, and going to:
Properties > Sources > Source/Binary > 1.6 (Or whatever version you need)
I already researched on how to install Eclipse Luna. One of the things to consider before installing Eclipse is to choose the JDK (planning to use JDK 8). It said that it is recommend that if I have an older version of Java, I need to uninstall it. But here's the problem: I don't know which I should uninstall. Here is the list of installed versions in my control panel (Windows 7 64bit):
Java 7
Java(TM) 6 Update 45
Java(TM) SE development kit 6 (i think this one but what's with (TM)?)
It is strongly recommended to specify what JVM (preferably a JDK) Eclipse should run in, via the eclipse.ini file. That way you can have any number of JDKs and/or JREs without problem. In fact, Eclipse also allows you to have multiple Java versions on your machine and each project in Eclipse can dictate exactly which one it uses. You can easily mix-and-match projects that use different Java versions, and they're all independent of the JVM that Eclipse itself is running in.
run java -version at the command line to see which one is in your PATH. This is the one that will run the Eclipse workspace.
Unless you have clear requirements to use older Java versions, I would recommend to uninstall all of them. And just have the latest JRE or better JDK installed.
In my case, I have a JRE to run the Eclipse workspace that is maintained by the Admin people and a private JDK (to provide additional tools, such as javadoc) to support the software development. You can have several Java versions installed (without having them in the PATH environment listed). You can point to them in the workspace settings or in specific Eclipse projects, e.g., to use a Java 6 for a certain project.
I think Eclipse Luna needs Java 7.
A Java 7 JRE/JDK is required for most of the Luna package downloads based on Eclipse 4.4.
In my opinion you can uninstall Java(TM) 6 Update 45 & Java(TM) SE development kit 6
I've an old machine running Windows XP 32.
Because Oracle dropped support for WXP 32 bits, I've manually installed the jdk following
the awesome answer here:
installing JDK8 on Windows XP - advapi32.dll error
I've however not added it yet to the JAVA_PATH, which is set to jdk 6. I don't know if it would harm or not to add it as well, but I want to be conservative here because a lot of programs in this machine need jdk 6. I don't want to break anything working now.
I'd like to toy around in eclipse to test the new Java 8 features. I've manually added the new jre 8 in the "Installed JREs" section under window -> preferences. In the compiler combo, the highest level available is 1.7 (installed jdk7 some time ago, this time using the official installer, but I still keep java 6 as the default in the system). I don't see any option to add the new level.
Consequently, when creating a new project using the new JRE, a warning is shown saying:
The current workspace uses a 1.4 JRE with compiler compliance level
1.6. This is not recommended and either the JRE or the compiler compliance level should be changed.
Seems a problem derived from the manual installation of the JDK.
I'm using Eclipse Kepler v4.3.1, but I have also tested this in older 3.x install with identical results.
Any help will be appreciated.
Support for Java 8 in Eclipse Kepler 4.3.2 is described here. This basically says specify
http://download.eclipse.org/eclipse/updates/4.3-P-builds/
as the 'Work with' site on Install New Software and select 'Eclipse Java 8 Support'.
Recent builds of Eclipse 4.4 Luna (since 18 March 2014) have Java 8 support included (but Luna is still under development).
Update:
Eclipse Luna (4.4) was released on 25 June 2014