"Unable to acquire application service" error while launching Eclipse

The /configuration/config.ini file should contain org.eclipse.core.runtime@start in the commaseparated osgi.bundles property. Here is the default osgi.bundles property, maybe it was (accidently) changed during some upgrade:

osgi.bundles=org.eclipse.equinox.common@2:start,org.eclipse.update.configurator@3:start,org.eclipse.core.runtime@start

You can if necessary override it by setting it as VM argument in /eclipse.ini:

-Dosgi.bundles=org.eclipse.equinox.common@2:start,org.eclipse.update.configurator@3:start,org.eclipse.core.runtime@start

Adding my two cents for those searching for "Ensure that the org.eclipse.core.runtime bundle is resolved and started":

Adding "arbitrary" bundles to the list of bundles just because it seems that they are missing is not always the best solution. Sometimes it can get quite frustrating, because those new plugins might depend on other missing bundles, which need even more bundles and so on...

So, before adding a new dependency to the list of required bundles, make sure you understand why the bundle is needed (the debugger is your friend!).

This question here doesn't provide enough information to make this a valid answer in all cases, but if you encounter the message that the org.eclipse.core.runtime is missing, try setting the eclipse.application.launchDefault system property to false, especially if you try to run an application which is not an "eclipse application" (but maybe just a headless runtime on top of equinox).

This link might come in handy: http://help.eclipse.org/indigo/index.jsp?topic=%2Forg.eclipse.platform.doc.isv%2Freference%2Fmisc%2Fruntime-options.html, look for the eclipse.application.launchDefault system property.

I have had the same problem, and here's how I solved it: I added the plugin "org.eclipse.core.runtime" in the "plugins" section on the "configuration" tab of the .product editor. I set it's start level to default and auto-start to true. I removed other plugins. My reasoning was this: Eclipse is complaining that the org.eclipse.core.runtime isn't started, so let's make sure that it does start, and that it's the only plugin that's starting.

My application ran fine after I did this. I then inspected the config.ini to see what changed, and saw that org.eclipse.core.runtime was now changed to org.eclipse.core.runtime@start. This is consistent with BalusC's suggestion, I just did it from the .product editor.