BOLD interview question

written : techniques of session management, merge two sorted array into single sorted array, few basic mathematical questions, order of having, group by, select, table etc 1st round : what is api ? how is soap different for restful service ? managing session out proc ? 2nd round : represent a tree with n node on code ? print all leaf nodes from this tree ? how can we represent this tree in rdbms ? print all leaf node from table you have made using query ? on click of button make the div of some color (apply class on div on click of button).