Exam1

Question 1

class header

Answer 1

public class C1 {

Question 2

main method header

Answer 2

public static void main (String [] args) {

Question 3

Random generator with seed

Answer 3

Random rand = new Random (seed);

Question 4

random number from rand, to preset max

Answer 4

rand.nextInt(MAX+1)

Question 5

create array myArr with howmany integers

Answer 5

int [] myArr = new int [howmany];

Question 6

set up Scanner scnr

Answer 6

Scanner scnr = new Scanner (System.in);

Question 7

for loop to howmany

Answer 7

for (int i = 0; i < howmany; i++) {

Question 8

set x to next typed in integer input

Answer 8

x = scnr.nextInt();

Question 9

package header

Answer 9

package P1;

Question 10

import Scanner

Answer 10

import java.util.Scanner;

Question 11

declare constant max and set as 2

Answer 11

final int MAX = 2;

Question 12

for loop internal: print each

Answer 12

System.out.print(numbers[i])

Question 13

if a method is not static…

Answer 13

it needs an object to call it, even in its own class.

e. g. c1 o1 = new c1();
o1. m1();

Question 14

if a class is hidden public…

Answer 14

it can’t be accessed from a different package.

Question 15

how to call a public static method in diff class, same package

Answer 15

e.g. class.method();

Question 16

how to call a public static method in diff class, diff package

Answer 16

import package, call class.method

e. g. import package.class;
class. method();

Question 17

how to call hidden public method in diff class, same package

Answer 17

create object, call object.

e. g. classname object=new classname();
object. method();

Question 18

how to call hidden public method in diff class, diff package

Answer 18

import package, create object, call object.
e.g. import package.class;
classname object=new classname();
object.method();

Question 19

private methods…

Answer 19

cannot be accessed outside their class.

Question 20

UML normal arrow means

Answer 20

uses or imports, for example a Random class from Java library. Read from stem to tip.

Question 21

UML diamond with line means

Answer 21

aggregates (read from diamond to line)

Question 22

aggregates indicates

Answer 22

an object or reference variable has been used

Question 23

deep copy function

Answer 23

a new (editable) copy, a separate object, does not continue to reference the original

Question 24

deep copy constructor example

Answer 24

C1 obj1 = new C1();
C1 obj2 = new C1(obj1);

Question 25

shallow copy function

Answer 25

link two objects that will keep updating each other

Question 26

shallow copy constructor example

Answer 26

``` C1 obj1 = new C1(); C1 obj2; obj2 = obj1; ```

Question 27

this.y

Answer 27

refers to a global variable y, where there is also a local variable y

Question 28

constructor

Answer 28

a special method that is named the same as the class name, and is public, with no return value statement

Question 29

example of default constructor

Answer 29

public C1 () {

Question 30

example of parameterized constructor

Answer 30

public C1(int y) {

Question 31

steps to make a deep copy in constructor class

Answer 31

1. default constructor 2. deep copy constructor

Question 32

steps to make a deep copy in main class

Answer 32

1. create obj1 2. deep copy constructor creates obj2 as referring to obj1

Question 33

interface contains

Answer 33

all abstract methods

Question 34

abstract class contains

Answer 34

at least one abstract method

Question 35

super keyword accesses

Answer 35

constructor in parent class

Question 36

Can normal class inherit normal class?

Answer 36

yes

Question 37

Can normal class inherit 2 abstract classes?

Answer 37

yes

Question 38

Can normal class inherit abstract class?

Answer 38

only if it overwrites any abstract classes

Question 39

Can abstract class inherit from normal class?

Answer 39

yes

Question 40

Can normal class inherit from interface?

Answer 40

normal class can implement interface

Question 41

UML symbol for interface

Answer 41

dotted line arrow

Question 42

UML open triangle arrow

Answer 42

extends or inherits

Question 43

polymorphism

Answer 43

create an object of parent that behaves like child

Question 44

polymorphism example

Answer 44

C1 obj = new C2(); where C1 is parent and C2 inherits from C1

Question 45

disadvantages of normal array

Answer 45

all data must be same type, fixed size, can't delete data (it would just revert to zero at that index, I think)

Question 46

add value to array

Answer 46

myArray[index]=value;

Question 47

make array

Answer 47

int [] myArray = new int [size];

Question 48

Steps to make Arraylist

Answer 48

``` import java.util.Arraylist Arraylist name = new Arraylist(); ```

Question 49

Steps to make a stack

Answer 49

``` import java.util.Stack Stack name = new Stack(); ```

Question 50

populate arraylist

Answer 50

name.add(value);

Question 51

arrays, Arraylists and stacks are

Answer 51

data structures

Question 52

insert array list value at a certain index

Answer 52

name.add(index, value);

Question 53

print arraylist

Answer 53

System.out.println(name);

Question 54

print array

Answer 54

for loop...

Question 55

remove value from arraylist

Answer 55

MyarrayList.remove(index);

Question 56

clear Arraylist

Answer 56

Myarraylist.removeAll;

Question 57

populate stack

Answer 57

myStack.push(value);

Question 58

insert stack value at index

Answer 58

nope. use something else. Stacks are for adding and taking away from the top.

Question 59

return top value of stack

Answer 59

stackName.peek();

Question 60

return and then delete top value of stack

Answer 60

stackName.pop();

Question 61

modifier codes in uml

Answer 61

+ public - private # protected

Question 62

deep copy vs shallow copy described like web links

Answer 62

shallow copy: Now B shares the same URL that A is using. deep copy: Downloaded, copied and pasted all the data from that source - once and done. Now B has all that as its own source, whose values match for the moment.