Most of the java project we use eclipse is tool for development . In general in eclipse if we use dot(.) operator near to object/class to see all the methods available.In some the rare weird scenario we will not get auto suggestion even after entering control+space as like below

This is due to some the software shortcut keys would have overridden the eclipse default behavior.

suggestion

Solution:

Go to  Window --> Preference -->Java -- >Editor -- > Content Assit -- > Advanced

Make sure that java proposals options are selected.

proposal