What this deck covers
This deck focuses on Object Creation And Storage Instantiation, giving you a quick way to review the definitions, rules, and examples that matter most for AP Computer Science a.
AP Computer Science a Flashcards: Object Creation And Storage Instantiation
Study Object Creation And Storage Instantiation in AP Computer Science a with focused flashcards that help you recognize the idea, recall the key rule, and apply it in practice-style prompts.
AP Computer Science a
Object Creation And Storage Instantiation
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What is the syntax to create a new object of class Car?
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ANSWER
Car myCar = new Car();. Standard object creation: declare variable, use new, call constructor.
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Flashcard 1: What is the syntax to create a new object of class Car?
Answer: Car myCar = new Car();. Standard object creation: declare variable, use new, call constructor.
Flashcard 2: How do you invoke a method on an object?
Answer: objectName.methodName();. Dot notation connects object reference to its methods.
Flashcard 3: Which method is called automatically when an object is created?
Answer: Constructor. Runs immediately when new keyword creates the object.
Flashcard 4: What is the result of 'Car[] cars = new Car[10];'?
Answer: Array of 10 Car references. Array holds references, objects created separately.
Flashcard 5: What is stored in a variable that holds an object reference?
Answer: Memory address of the object. References are pointers to objects in heap memory.
Flashcard 6: What is the purpose of the 'new' keyword?
Answer: To create new objects. Allocates memory and initializes objects dynamically.
Flashcard 7: Identify the type of 'Car myCar;' where Car is a class.
Answer: Object reference declaration. Declares variable to hold reference to Car object.
Flashcard 8: How do you call a constructor when creating an object?
Answer: Using new keyword with class name. Constructor follows class name after new keyword.
Flashcard 9: What happens if you attempt to use an uninitialized object reference?
Answer: NullPointerException. Thrown when accessing methods on null references.
Flashcard 10: Identify the part of 'Car myCar = new Car()' that is a constructor call.
Answer: new Car(). Constructor call invokes the Car() constructor method.
Flashcard 11: How can you declare an object reference without instantiation?
Answer: Car myCar;. Creates reference variable without allocating object memory.
Flashcard 12: What happens if you attempt to use an uninitialized object reference?
Answer: NullPointerException. Thrown when accessing methods on null references.
Flashcard 13: What is the significance of 'null' in object references?
Answer: Indicates no object is referenced. Default value for uninitialized object references.
Flashcard 14: Identify the return type of a constructor.
Answer: Constructors have no return type. Constructors initialize but don't return values.
Flashcard 15: What is the result of using 'new' keyword on a class?
Answer: A new instance of the class is created. Each use of new creates a separate object instance.
Flashcard 16: What does 'new' keyword do in object creation?
Answer: Allocates memory for the object. Reserves space in heap for object's instance variables.
Flashcard 17: Which operator is used to access an object's methods?
Answer: Dot operator (.). Accesses methods and variables of an object instance.
Flashcard 18: How do you create an array of objects?
Answer: ClassName[] arrayName = new ClassName[size];. Creates array to hold object references, not objects.
Flashcard 19: What happens if no constructor is defined in a class?
Answer: A default constructor is provided by Java. Java automatically provides a parameterless constructor.
Flashcard 20: What is the significance of 'null' in object references?
Answer: Indicates no object is referenced. Default value for uninitialized object references.
Flashcard 21: What does 'null' signify for an object reference?
Answer: No object is referenced. Special value indicating absence of object reference.
Flashcard 22: What is the purpose of the 'new' keyword?
Answer: To create new objects. Allocates memory and initializes objects dynamically.
Flashcard 23: What does 'myCar = new Car();' do?
Answer: Instantiates a Car object. Allocates memory and initializes new Car object.
Flashcard 24: Identify the error: 'Car myCar = new Car()'
Answer: Missing semicolon. Statement terminator required after constructor call.
Flashcard 25: How do you call a constructor when creating an object?
Answer: Using new keyword with class name. Constructor follows class name after new keyword.
Flashcard 26: Identify the type of 'Car myCar;' where Car is a class.
Answer: Object reference declaration. Declares variable to hold reference to Car object.
Flashcard 27: How do you instantiate an object with a parameterized constructor?
Answer: new ClassName(parameters). Pass arguments to constructor for custom initialization.
Flashcard 28: What happens if no constructor is defined in a class?
Answer: A default constructor is provided by Java. Java automatically provides a parameterless constructor.
Flashcard 29: Which operator is used to access an object's methods?
Answer: Dot operator (.). Accesses methods and variables of an object instance.
Flashcard 30: Identify the return type of a constructor.
Answer: Constructors have no return type. Constructors initialize but don't return values.
Flashcard 31: What is initialized when an object is instantiated?
Answer: Object's fields. Constructor sets initial state of instance variables.
Flashcard 32: What does an object reference variable store?
Answer: Address of the object. Holds memory location where object data is stored.
Flashcard 33: Identify the error: 'Car myCar = new Car()'
Answer: Missing semicolon. Statement terminator required after constructor call.
Flashcard 34: What is the result of 'Car myCar = null;'?
Answer: myCar points to no object. Reference is explicitly set to point nowhere.
Flashcard 35: How do you create an array of objects?
Answer: ClassName[] arrayName = new ClassName[size];. Creates array to hold object references, not objects.
Flashcard 36: Correct the error: 'Car myCar = Car();'
Answer: Car myCar = new Car();. Missing 'new' keyword required for object creation.
Flashcard 37: In Java, what is a constructor used for?
Answer: Initializing a new object. Sets initial values for object's instance variables.
Flashcard 38: What is the result of using 'new' keyword on a class?
Answer: A new instance of the class is created. Each use of new creates a separate object instance.
Flashcard 39: What is the difference between class and object?
Answer: Class defines; object is instance. Class is template; object is concrete implementation.
Flashcard 40: What does 'myCar = new Car();' do?
Answer: Instantiates a Car object. Allocates memory and initializes new Car object.
Flashcard 41: State the relationship between class and object.
Answer: Class is a blueprint; object is an instance. Class defines structure; objects are actual instances.
Flashcard 42: What is initialized when an object is instantiated?
Answer: Object's fields. Constructor sets initial state of instance variables.
Flashcard 43: What is the role of the 'this' keyword?
Answer: Refers to the current object instance. References the object whose method is being called.
Flashcard 44: What is stored in a variable that holds an object reference?
Answer: Memory address of the object. References are pointers to objects in heap memory.
Flashcard 45: What does 'new' keyword do in object creation?
Answer: Allocates memory for the object. Reserves space in heap for object's instance variables.
Flashcard 46: Correct the error: 'Car myCar = Car();'
Answer: Car myCar = new Car();. Missing 'new' keyword required for object creation.
Flashcard 47: Identify the keyword used in Java for object instantiation.
Answer: new. Creates objects by allocating memory and calling constructor.
Flashcard 48: How do you invoke a method on an object?
Answer: objectName.methodName();. Dot notation connects object reference to its methods.
Flashcard 49: Identify the keyword used in Java for object instantiation.
Answer: new. Creates objects by allocating memory and calling constructor.
Flashcard 50: What is the purpose of a constructor?
Answer: To initialize new objects. Special method that sets up new object instances.
Flashcard 51: What is the result of 'Car myCar = null;'?
Answer: myCar points to no object. Reference is explicitly set to point nowhere.
Flashcard 52: What is the role of the 'this' keyword?
Answer: Refers to the current object instance. References the object whose method is being called.
Flashcard 53: What is the difference between class and object?
Answer: Class defines; object is instance. Class is template; object is concrete implementation.
Flashcard 54: Find the error: 'new Car myCar = new Car();'
Answer: Remove 'new' before 'Car'. 'new' should only appear before constructor call.
Flashcard 55: Which method is called automatically when an object is created?
Answer: Constructor. Runs immediately when new keyword creates the object.
Flashcard 56: How do you instantiate an object with a parameterized constructor?
Answer: new ClassName(parameters). Pass arguments to constructor for custom initialization.
Flashcard 57: Find the error: 'new Car myCar = new Car();'
Answer: Remove 'new' before 'Car'. 'new' should only appear before constructor call.
Flashcard 58: What is the result of 'Car[] cars = new Car[10];'?
Answer: Array of 10 Car references. Array holds references, objects created separately.
Flashcard 59: How can you declare an object reference without instantiation?
Answer: Car myCar;. Creates reference variable without allocating object memory.
Flashcard 60: State the relationship between class and object.
Answer: Class is a blueprint; object is an instance. Class defines structure; objects are actual instances.
Flashcard 61: What is the consequence of not using 'new' keyword?
Answer: No object is instantiated. Objects must be created with new keyword.
Flashcard 62: Identify the part of 'Car myCar = new Car()' that is a constructor call.
Answer: new Car(). Constructor call invokes the Car() constructor method.
Flashcard 63: In Java, what is a constructor used for?
Answer: Initializing a new object. Sets initial values for object's instance variables.
Flashcard 64: What does an object reference variable store?
Answer: Address of the object. Holds memory location where object data is stored.
Flashcard 65: What is the consequence of not using 'new' keyword?
Answer: No object is instantiated. Objects must be created with new keyword.
Flashcard 66: Identify the error: 'Car myCar = new Car;'
Answer: Missing parentheses: new Car();. Constructor call requires parentheses after class name.
Flashcard 67: What is the syntax to create a new object of class Car?
Answer: Car myCar = new Car();. Standard object creation: declare variable, use new, call constructor.
Flashcard 68: What does 'null' signify for an object reference?
Answer: No object is referenced. Special value indicating absence of object reference.
Flashcard 69: Identify the error: 'Car myCar = new Car;'
Answer: Missing parentheses: new Car();. Constructor call requires parentheses after class name.
Flashcard 70: What is the default constructor?
Answer: A no-argument constructor provided by Java. Takes no parameters and provides basic initialization.