Spring Tool Suite (STS) 3.5.0 - org.codehaus.groovy.eclipse is unknown in the solver

Question 1

Help -> Check for updates

Problem Occured

"JDT Core patch with Java 8 Support for Groovy-Eclipse plugin" is not applicable to the current configuration and will not be installed.

An internal error occurred during: "Searching alternate solutions...".

org.codehaus.groovy.eclipse 2.9.0.xx-201403261719-e43j8 is unknown in the solver!

If you get this error, then these are the steps to fix it:

Help

About Spring Tool Suite

Installation Details

Eclipse Java Development Tools Patch with Java 8 support (for Kepler SR2)

Uninstall...

restart

Then to verify that the error is gone:

Help -> Check for updates

No updates were found.

It should be ok now. But you need to install the Java 8 support

Then follow these steps:

Help

Install new software...

Work with: SpringSource Update Site for Eclipse 4.3 - http://download.springsource.com/release/TOOLS/update/e4.3

[x] Groovy-Eclipse

Next

Next

I accept

Finish

Restart

That should do it.

Question 2

I had the same problem. Check if groovy-eclipse is installed. If it is not, then you need to install it first then install STS.

Check this website for installation https://www.function1.com/2016/06/installing-eclipse-groovy-plugin