I am a newbie in Ubuntu. I want install ADT (Android Development Tools) Eclipse, but there is a popup like this:
Please someone help me to solve my problem.
This is expected, and explained in ADT site:
Read and accept the license agreements, then click Finish.
If you get a security warning saying that the authenticity or validity of the software can't be established, click OK.
Many Eclipse plugins are unsigned, and this is just one of them. (See also a similar question in Stack Overflow)