Geometric Senior Software Engineer Java interview questions

1. For online test all core java questions. Two small logical programs in 40 mins. Programs which involves % operator and loop etc. logical. It was online through naukari.com 2.After one week HR called me and scheduled one technical interview. He asked questions on core java. some questions: -What is composition? -What is annotations and deeper into it. How source level annotations works in java(This I couldn't answer) -Even our custom exception class inherits form Exception and RuntineException also subclass of Exception . Then what makes our class Checked and all Subclasses of RTE as Unckecked. -How to create the immutable class -How to create own Singleton class -How to add duplicate objects in Set (Overall 40 mins discussion) 3. For manager discussion it was just normal discussion was little bit long.(More than 1 hr) 4. For F2F discussion they called me. Actually this discussion was with Simmens PLM panel @Pune. They asked some questions on java(about annonymous inner class declared in Method and method of it accessing static member of method itself). The main focus was on the optimization and how you approach the given problem. -Wirte a function to check if duplicates chars are present in array or not: I approached the problem very straight forward I tried to solve using Map and loop only once. But they expecting very different approach which will be the optimal solution. Something like as the chars(suppose ASCII) can take only 128 values and so best approach was to create the array of size 128 and use char's asscii value (int ) as index. so while looping first time only you can find. -How to find a broken link in linked list: They were expecting solution using tow pointers one accesses just next element and one next to next. So if there is back link to wrong element (say from last element to 3rd instead of 1st) one time both will point the same. -They asked puzzles.Search on net the same one. -They asked to write the program and they pointed out syntax and typo errors also. -Be very focused and try to give multiple solutions for the problem.