[eclipse] How to change default JRE for all Eclipse workspaces?

I have one JRE in C:\Program Files (x86)\Java\jre6 and that was the only one at the time I installed Eclipse. I have subsequently installed a complete JDK in C:\home\SFTWR\jdk1.6.0_21 and changed my JAVA_HOME environment variable to that. However, every time I start a new Eclipse workspace, it only picks up the old JRE and I have to manually remove it and add the new one.

How do I bind my Eclipse install to the new JDK so that every new workspace points to that only? I checked eclipse.ini but there was no reference there to which JRE to go to.

UPDATE:

I went into Prefs->Java->Installed JREs, added the new location, marked it as default, removed the other, and it was effective only for the current workspace. However, when I opened a new workspace, only the old JRE was available. So this didn't change the core Eclipse config that is applicable across all (at least new) workspaces

I ran into a similar issue where eclipse was not using my current %JAVA_HOME% that was on the path and was instead using an older version. The documentation points out that if no -vm is specified in the ini file, eclipse will search for a shared library jvm.dll This appears in the registry under the key HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\JavaSoft\Java Runtime Environment that gets installed when using the windows java installer (key might be a bit different based on 64-bit vs 32-bit, but search for jvm.dll). Because it was finding this shared library on my path before the %JAVA_HOME%/bin, it was using the old version.

Like others have stated, the easiest way to deal with this is to specify the specific vm you want to use in the eclipse.ini file. I'm writing this because I couldn't figure out how it was still using the old version when it wasn't specified anywhere on the path or eclipse.ini file.

See link to doc below: http://help.eclipse.org/kepler/topic/org.eclipse.platform.doc.isv/reference/misc/launcher.html?cp=2_1_3_1

Finding a VM and using the JNI Invocation API

The Eclipse launcher is capable of loading the Java VM in the eclipse process using the Java Native Interface Invocation API. The launcher is still capable of starting the Java VM in a separate process the same as previous version of Eclipse did. Which method is used depends on how the VM was found.

No -vm specified

When no -vm is specified, the launcher looks for a virtual machine first in a jre directory in the root of eclipse and then on the search path. If java is found in either location, then the launcher looks for a jvm shared library (jvm.dll on Windows, libjvm.so on *nix platforms) relative to that java executable.

• If a jvm shared library is found the launcher loads it and uses the JNI invocation API to start the vm.
• If no jvm shared library is found, the launcher executes the java launcher to start the vm in a new process.

-vm specified on the command line or in eclipse.ini

Eclipse can be started with "-vm " to indicate a virtual machine to use. There are several possibilities for the value of :

• directory: is a directory. We look in that directory for:
  • (1) a java launcher or
  • (2) the jvm shared library.

If we find the jvm shared library, we use JNI invocation. If we find a launcher, we attempt to find a jvm library in known locations relative to the launcher. If we find one, we use JNI invocation. If no jvm library is found, we exec java in a new process.

• java.exe/javaw.exe: is a path to a java launcher. We exec that java launcher to start the vm in a new process.

• jvm dll or so: is a path to a jvm shared library. We attempt to load that library and use the JNI Invocation API to start the vm in the current process.

try to change the order: right click on you project-> BuildPath->Configure...->Order and Export tab -> move jre7 UP.

Open the Java > Installed JREs preference page. Check the box on the line for the JRE that you want to assign as the default JRE in your workbench. If the JRE you want to assign as the default does not appear in the list, you must add it. Click OK.

Source-http://help.eclipse.org/juno/index.jsp?topic=%2Forg.eclipse.jdt.doc.user%2Ftasks%2Ftask-assign_default_jre.htm

The Installed JREs is used for what JREs to execute for your downstream Java projects and servers. As far as what JVM or JRE that is used to execute Eclipse process (workbench) itself that is controlled by your environment, history and eclipse.exe binary. So eclipse.exe itself decides what JRE Eclipse will execute itself with, not installed JREs preferences since those are not read until OSGi framework is up and running which is loaded after the JVM/JRE is picked.

So for new workspaces, Eclipse is going to use its currently executing JRE to populate the JRE prefs.

The best way I know how is to force eclipse.exe to use the JRE that you tell it via the -vm switch. So in your eclipse.ini do this:

-startup
plugins/org.eclipse.equinox.launcher_1.2.0.v20110502.jar
--launcher.library
plugins/org.eclipse.equinox.launcher.win32.win32.x86_64_1.1.100.v20110502
-vm
/path/to/exactly/what/jre/you/want/as/default/javaw.exe
...

I have faced with the same issue. The resolve: - Window-->Preferences-->Java-->Installed JREs-->Add... - Right click on your project-->Build Path-->Configure Build Path-->Add library-->JRE system library-->next-->WorkSpace Default JRE

In eclipse go to

Window-> Java -> Installed JREs

You can remove your current installed jre and add the jdk by specifying the path to where the jdk is installed.

when you select run configuration, there is a JRE tap up next the main tap, select "Workspace default JRE(JDK1.7)".

Be sure to use the jdk in Prefs->Java->Installed JREs ->Execution Environment

My answer will overlap with amphibient's while adding on to it.

Your JAVA_HOME variable is fine, but you also need to append the following to your Path variable :

;%JAVA_HOME%\bin

This will allow your applications in your Windows environment to access your JDK. You should also restart your computer once you've added these environment variables before checking out if they work. In my case, even logging out and then back in didn't work : I had to completely restart.

If you want to check if the environment variables are set correctly, you can open up a command prompt and type >echo %JAVA_HOME and >echo %Path% to see if those variables are working correctly. While snooping around for solutions, I have also run into people claiming that they need to add quotations marks (") around the environment variables to make them work correctly ("%JAVA_HOME%"\bin) if your JAVA_HOME path includes spaces. I thought that this was my case at first, but after doing a full restart my variables seemed to work correctly without quotation marks despite the spaces.

On windows I've tried different approaches - setting JAVA_HOME, JRE_HOME and extending the PATH to point to the desiered jre18 but nothing helped - disabling the JRE17 in the java control panel didn't helped either

What helped me out was to force eclipse to use the appropriate JRE in the eclipse.ini file e.g.

-vm C:\java\jdk1.8.0_111\jre\bin\javaw.exe

I navigated to:

Eclipse>Pref>Java>Installed JRE>Search...

2 of them popped up and I checked the latest one. Before I did this I also went to About>Check for Updates and updated it. I didn't have to reinstall any JRE or JDK either. I might have done it a while back, except it was with 1.6 not 1.4. Hope that helps!