Accessing and Modifying Array Elements in Java
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Questions and Answers

What is the purpose of a constructor in Java?

  • To access values from an array
  • To create multiple instances of a class
  • To declare local variables within a method
  • To initialize the state of new objects (correct)
  • What is a common bug associated with constructors?

  • Indexing, which helps access elements in an array
  • Abstraction, which hides implementation details
  • Encapsulation, which separates behavior from state
  • Shadowing, which re-declares fields as local variables (correct)
  • In Java, what does encapsulation aim to achieve?

  • Creating multiple arrays of different types
  • Hiding implementation details from clients (correct)
  • Initializing object data to default values
  • Declaring multiple constructors for a class
  • What happens if a class in Java has no constructor defined?

    <p>Java gives it a default constructor with no parameters setting all fields to 0</p> Signup and view all the answers

    What is the purpose of an array index in Java?

    <p>To access specific elements within an array</p> Signup and view all the answers

    What does the term 'shadowing' refer to in Java?

    <p>Re-declaring fields as local variables within methods</p> Signup and view all the answers

    What method is used to set every element of an array to a given value?

    <p>fill(array, value)</p> Signup and view all the answers

    Which loop type is commonly used with ArrayLists to iterate over elements?

    <p>Enhanced For Loop</p> Signup and view all the answers

    What is the purpose of the toString method when used with an array?

    <p>Return a string representing the array</p> Signup and view all the answers

    Which class provides wrapper classes for primitive data types in Java?

    <p>Wrappers &amp; Auto-Boxing</p> Signup and view all the answers

    In ArrayLists, what method is used to add a new value at a specific location?

    <p>.add()</p> Signup and view all the answers

    What differentiates Arrays from ArrayLists regarding size flexibility?

    <p>Arrays never change in size</p> Signup and view all the answers

    What is the main difference between a class and an object?

    <p>A class is a template for new types of objects, while an object represents a single instance of the class.</p> Signup and view all the answers

    What does each object have its own copy of in terms of fields?

    <p>Each object has its own copy of each field inside the class.</p> Signup and view all the answers

    What happens if client code tries to access private fields outside the class?

    <p>Client code will not compile if it accesses private fields.</p> Signup and view all the answers

    What is the purpose of an accessor method in object-oriented programming?

    <p>An accessor method allows clients to examine the state of an object.</p> Signup and view all the answers

    What is the purpose of a mutator method in OOP?

    <p>A mutator method modifies the state of an object.</p> Signup and view all the answers

    What defines existence inside each object of a class and gives behavior to each object?

    <p>Instance Methods</p> Signup and view all the answers

    What is the correct way to access the value of an element in an array named 'a' at a specific index?

    <p>a.name[index];</p> Signup and view all the answers

    Which statement about the 'Length Field' in Java arrays is true?

    <p>It is accessed using the format a.name.length.</p> Signup and view all the answers

    What is the correct syntax for initializing an array named 'results' with double values 3.4 and -0.5?

    <p>a.double[] results = {3.4, -0.5};</p> Signup and view all the answers

    What will happen if you attempt to access an index outside the legal range of an array in Java?

    <p>It will throw an 'ArrayIndexOutOfBoundsException'.</p> Signup and view all the answers

    Which of the following is a limitation when working with arrays in Java?

    <p>You can directly compare arrays using '==' operator.</p> Signup and view all the answers

    When using a 'For Loop' to access elements in an array, how do you assign a value to each element?

    <p>= operator is used on index with 'arrayName[index]'.</p> Signup and view all the answers

    What is the main purpose of version control systems in software development?

    <p>Identifying and storing different versions of software components</p> Signup and view all the answers

    What is a key feature of centralized version control systems?

    <p>Using a single master repository to store all versions of software components</p> Signup and view all the answers

    How do distributed version control systems differ from centralized VC systems?

    <p>Developers create clones of the project repo on their own computers in distributed systems</p> Signup and view all the answers

    What happens in a centralized VC system if multiple developers try to work on the same component simultaneously?

    <p>The system warns other users that someone else is working on the component</p> Signup and view all the answers

    When using a distributed VC system, where are new versions of files maintained before committing changes?

    <p>On individual developer's computers in private repositories</p> Signup and view all the answers

    What is the key difference between centralized and distributed VC systems in terms of project repository location?

    <p>Distributed systems have the main project repo created on a server instead of local computers</p> Signup and view all the answers

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