Core Java Mock Interview for Automation Testers – Real Questions & Answers

11/25/24 •

Summaries by topic

• English

This mock interview for Java automation testers covers core topics including iterators, lists and sets, array manipulation, string functions, object-oriented programming principles, and the Final keyword. The candidate demonstrates a good understanding of these concepts and implements several examples in code, although there were minor issues in a few code examples due to limited preparation time.

Iterators vs. List Iterators

• 00:00:06 Iterators are used to iterate through collections in Java, providing forward iteration only with hasNext and next methods. List iterators extend iterator functionality to allow both forward and backward iteration, with methods like hasPrevious and previous, and apply specifically to list interfaces.

List vs. Set

• 00:01:43 Lists and sets are distinct collection types in Java. Lists are ordered and indexed, allowing duplicate values and multiple null values, while sets are unordered and do not allow duplicates, accepting only one null value. Lists utilize iterators and list iterators, whereas sets only use iterators.

Array Reversal

• 00:02:35 The interviewee demonstrates how to copy elements from one array to another in reverse order using a loop and indexing. The program iterates through the first array in reverse order and copies each element to the corresponding index of the second array, successfully reversing the array elements.

String Functions

• 00:14:29 Java String class provides several functions such as toUpperCase(), toLowerCase(), trim(), concat(), equals(), isEmpty(), and charAt(). These functions are used to modify, compare, check for emptiness, and retrieve characters at specific indices within strings.

Object Oriented Programming

• 00:15:44 Object-oriented programming (OOP) languages often include key features like classes, objects, encapsulation, polymorphism, inheritance, and abstraction. The existence of these features in a language suggests that it is an object-oriented programming language.