Different search engines work differently, for example some job boards / ATS will throw an error if you don’t have proper brackets.

But LinkedIn, will interpret your 2nd search like this (Java AND Spring AND Hibernate) OR (Hibernet AND Multithreading)

• Learn basics of how AND, OR, ( ), ” ” are to be used.
• Be more candidate centric & less JD centric
• NOT is the superman of sourcing & the least used operator by Recruiters, see how you can embed it in your searches.

Lastly, don’t search. But play with the search engine.
Note: Look at this answer & also the attached document on this question. You’d get an idea of how sourcing models are built.
You can join recruitingmonk’s sourcing workshop, for details check this link

This is difficult to achieve in a search.

Yes, Google search is very effective & has its own advantages.

For example, if you want to perform unlimited searches on linkedin data then you can opt for Google coz it is free.

Secondly to find contact details across the web, search alumnis, communities etc etc.

Trying to understand their personal goals. Coz someone of that level would have had some plans or might have some plans to do something which will create an impact in their line of biz. Try to understand if they wanted to build something or have planned to do so in a similar line of biz as yours (your company). That can be a good motivation.

Secondly, just ask them if you get to work with us how do you think you can bring an impact over a period of time, let’s say from 3 months 12 months. How & what impact can you bring in?

You can ask these kind of questions to gauge who can fit in well & who is coming with that extra zeal which can give him an edge over the other.