Which of the following are incorrect form of StringBuffer class constructor ?

Correct Answer: Immutable classes are Java classes whose objects can not be modified once created Any modification in Immutable object result in new object For example is String is immutable in Java Mostly Immutable are also final in Java, in order to prevent sub class from overriding methods in Java which can compromise Immutability You can achieve same functionality by making member as non final but private and not modifying them except in constructor

Correct Answer: 'ViewState' is specific to a page in a session 'SessionState' is specific to user specific data that can be accessed across all pages in the web application

Correct Answer: There are lots of ways to solve the issue of callback hells: 1 Modularization: break callbacks into independent functions 2 Use a control flow library, like async 3 Use generators with Promises 4 Use async/await (note that it is only available in the latest v7 release and not in the LTS version)

Correct Answer: The Spring IoC is responsible for creating the objects,managing them (with dependency injection (DI)), wiring them together, configuring them, as also managing their complete lifecycle

Correct Answer: ArrayList and LinkedList both implements List interface and maintains insertion order Both are non synchronized classes But there are many differences between ArrayList and LinkedList classes that are given below ArrayList V/s LinkedList :: 1) ArrayList internally uses dynamic array to store the elements Whereas LinkedList internally uses doubly linked list to store the elements 2) Manipulation with ArrayList is slow because it internally uses array If any element is removed from the array, all the bits are shifted in memory Whereas Manipulation with LinkedList is faster than ArrayList because it uses doubly linked list so no bit shifting is required in memory 3) ArrayList class can act as a list only because it implements List only Whereas LinkedList class can act as a list and queue both because it implements List and Deque interfaces 4) ArrayList is better for storing and accessing data Whereas LinkedList is better for manipulating data

Correct Answer: ello

Explanation:

deleteCharAt() method deletes the character at the specified index location and returns the resulting StringBuffer object.

So after deleting the character at 0 ie 'H', the string returns 'ello' as the output.

Correct Answer: Cocoa is for Mac App development and cocoa touch is for apples touch devices - that provide all development environment

Correct Answer: An app can get into InActive state when the user locks the screen or the system prompts the user to respond to some event eg SMS message, incoming call etc

Correct Answer: IOS development requires Intel-based Macintosh computer and iOS SDK

Correct Answer: ARC is a compiler-level feature that simplifies the process of managing the lifetimes of Objective-C objects Instead of you having to remember when to retain or release an object, ARC evaluates the lifetime requirements of your objects and automatically inserts the appropriate method calls at compile time