Eclipse IDE - Error: Build path specifies execution environment Java SE 1.7

Question

In Eclipse, I am getting an error:

Build path specifies execution environment Java SE 1.7.
There are no JREs installed in the workspace that are st

Answer 1

Sounds like what I had after installing a newer Eclipse.

My solution:

Window->Preferences, Java->Installed JREs->Execution Environment.

Click the correct environment in the left panel, probably JavaSE-jre7

If the checkbox in the right panel is empty, check it.

If it's checked, but it isn't named jre7 [perfect match] then find the one in the left panel that does have 'perfect match' on the right and check that instead.