Terminology

Question 1

What is a class in java

Answer 1

A class describes a particular kind of object. It can contain related methods and data members (variables).

Question 2

What is special about classes in java

Answer 2

must have the same name as the file it is contained in

Question 3

Give an example of a class

Answer 3

public class myClass(){

Question 4

What is a constructor in java

Answer 4

A special type of instance method that creates a new object.

Question 5

What is special about a constructor in java

Answer 5

In Java, constructors have the same name as their class and have no return value in their declaration.

Question 6

What is an example of a constructor

Answer 6

public class myClass{
          // a constructor that takes no parameters

Question 7

What is a declaration in java

Answer 7

A statement that creates a variable, method, or class identifier and its associated attributes but doesn’t necessarily allocate storage for variables or define an implementation for methods.

Question 8

What is special about declaration in java

Answer 8

Classes are always defined when they are declared, i.e., a class cannot be declared and then have its body defined elsewhere.

Question 9

Give an example of declaration in java

Answer 9

the variable var is declared

int var;

Question 10

What is definition in java

Answer 10

Similar to a declaration except that it also reserves storage (for variables) or provides implementations (for methods).

Question 11

Give an example of definition in java

Answer 11

public void myMethod(){
/* A method is defined if it has brackets, a space where code goes that says what the method does. */

Question 12

What is initializing in java

Answer 12

an assignment that sets the starting value of a variable.

Question 13

What is an example of initializing in java

Answer 13

Example 1: an integer var is declared, defined, and initialized to the value 2.
int var = 2;

Question 14

What is instantiating in java

Answer 14

To allocate storage for an object in memory (involves the keyword new).

Question 15

what is an instantiation always followed by

Answer 15

a constructor call that initializes the object

Question 16

give an example of instantiation in java

Answer 16

the keyword new instantiates the object below. An instantiation is always followed by a constructor call that initializes the object.
      MyClass myObject = new MyClass(/*parameters*/);

Question 17

What is a method in java

Answer 17

a collection of code found within a class. If the data members of a class are nouns, the methods are the verbs (the action).

Question 18

Give an example of a method

Answer 18

public class myClass{
public void myMethod(){

Question 19

What is an object in java

Answer 19

The principal code building block of Java programs.

Question 20

What does an object in a program consist of

Answer 20

Each object in a program consists of both variables (data) and methods (functionality).

Question 21

What is a parameter in java

Answer 21

a variable or object passed into a method.

Question 22

What is an example of a parameter

Answer 22

public void myMethod(int var1, double var2){

Question 23

what is a primitive in java

Answer 23

A variable defined with a primitive data type: byte, short, int, long, float, double, char, or boolean.

Question 24

What is a typecast in java

Answer 24

(1) to demote a variable from a larger capacity data type to a smaller one. (2) to re-establish the class of an object. The cast associates itself with the expression to its immediate right.

Question 25

Give an example of typecasting in java

Answer 25

Example 1: A double var is created and then typecast via “(int)” to a variable of integer type ans.
double var = 3;
int ans = (int) var;

Question 26

What is use/read in java

Answer 26

the use of a variable in the right hand side of an assignment statement.

Question 27

Give an example of use/read in java

Answer 27

Example: an integer var is declared and used in the initialization of integer ans.
int var = 2;
int ans = Math.pow(var,2);