Eclipse appears some sites could not being found. See the error log for more detail. Error resolution
Some sites could not be found. See the error log for more detail. This means that there is a problem in setting the update sites, the problem is that the site cannot be found or found. This is because when we use Eclipse's help-->install new software, adding the installation path can sometimes happen when we can't find it, but we don't have the problem of deleting it in time.
Knowing the source of the problem is a good solution.
Open window-->preferences-->install/update->available software site as follows.
Remove the site that appears in the pop-up window from here. Don't forget that there is a very good search function here, that is, type filter text is entered here.
After the deletion, the problem is solved.
http://blog.csdn.net/dijason/article/details/8491558