MAC:Mon Oct 25:09:33:interfaces> ls
Circle.java Shape.java
MAC:Mon Oct 25:09:33:interfaces> javac *.java
MAC:Mon Oct 25:09:33:interfaces> jshell
|  Welcome to JShell -- Version 17
|  For an introduction type: /help intro

jshell> Circle c = new Circle(10);
|  Error:
|  cannot find symbol
|    symbol:   class Circle
|  Circle c = new Circle(10);
|  ^----^
|  Error:
|  cannot find symbol
|    symbol:   class Circle
|  Circle c = new Circle(10);
|                 ^----^

jshell> /open Shape.java

jshell> /open Circle.java

jshell> Circle c = new Circle(10);
c ==> Circle@6e8cf4c6

jshell> c.area()
$4 ==> 314.1592653589793

jshell> c.diameter()
$5 ==> 20.0

jshell> c.perimeter()
$6 ==> 62.83185307179586

jshell> Shape s = new Shape();
|  Error:
|  Shape is abstract; cannot be instantiated
|  Shape s = new Shape();
|            ^---------^

jshell> s = new Circle(10);
|  Error:
|  cannot find symbol
|    symbol:   variable s
|  s = new Circle(10);
|  ^

jshell> Shape s = new Circle(10);
s ==> Circle@27973e9b

jshell> s.area()
$8 ==> 314.1592653589793

jshell> /exit
|  Goodbye
MAC:Mon Oct 25:09:39:interfaces> wget https://faculty.ncssm.edu/~morrison/currentClasses/4240/Oct/25Oct21/Rectangle.java
--2021-10-25 09:39:40--  https://faculty.ncssm.edu/~morrison/currentClasses/4240/Oct/25Oct21/Rectangle.java
SSL_INIT
Resolving faculty.ncssm.edu (faculty.ncssm.edu)... 192.154.43.11
Connecting to faculty.ncssm.edu (faculty.ncssm.edu)|192.154.43.11|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 443 [text/plain]
Saving to: ‘Rectangle.java’

Rectangle.java      100%[===================>]     443  --.-KB/s    in 0s      

2021-10-25 09:39:40 (35.2 MB/s) - ‘Rectangle.java’ saved [443/443]

MAC:Mon Oct 25:09:39:interfaces> javac *.java
MAC:Mon Oct 25:09:39:interfaces> jshell
|  Welcome to JShell -- Version 17
|  For an introduction type: /help intro

jshell> Shape s = new Rectangle(6,8);
|  Error:
|  cannot find symbol
|    symbol:   class Shape
|  Shape s = new Rectangle(6,8);
|  ^---^
|  Error:
|  cannot find symbol
|    symbol:   class Rectangle
|  Shape s = new Rectangle(6,8);
|                ^-------^

jshell> /open Shape.java

jshell> /open Circle.java

jshell> /open Rectangle.java

jshell> Shape s = new Rectangle(6,8);
s ==> Rectangle@34c45dca

jshell> s.area()
$5 ==> 48.0

jshell> s.diameter()
$6 ==> 10.0

jshell> s.perimeter
|  Error:
|  cannot find symbol
|    symbol:   variable perimeter
|  s.perimeter
|  ^---------^

jshell> s.perimeter()
$7 ==> 28.0

jshell> ArrayList<Shape> al = new ArrayList<>();
al ==> []

jshell> al.add(new Circle(10));
$9 ==> true

jshell> al.add(new Rectangle(6,8));
$10 ==> true

jshell> al
al ==> [Circle@3d494fbf, Rectangle@1ddc4ec2]

jshell> /exit
|  Goodbye
MAC:Mon Oct 25:09:46:interfaces> vi Rectangle.java
MAC:Mon Oct 25:09:47:interfaces> javac *.java
MAC:Mon Oct 25:09:47:interfaces> jshell
|  Welcome to JShell -- Version 17
|  For an introduction type: /help intro

jshell> Shape s = new Rectangle(6,8);
|  Error:
|  cannot find symbol
|    symbol:   class Shape
|  Shape s = new Rectangle(6,8);
|  ^---^
|  Error:
|  cannot find symbol
|    symbol:   class Rectangle
|  Shape s = new Rectangle(6,8);
|                ^-------^

jshell> /open Shape.java

jshell> /open Circle.java

jshell> /open Rectangle.java

jshell> Shape s = new Rectangle(6,8);
s ==> Rectangle@34c45dca

jshell> s.area()
$5 ==> 48.0

jshell> s.numSides()
|  Error:
|  cannot find symbol
|    symbol:   method numSides()
|  s.numSides()
|  ^--------^

jshell> s.getClass()
$6 ==> class Rectangle

jshell> s = new Circle(10);
s ==> Circle@312b1dae

jshell> s.area()
$8 ==> 314.1592653589793

jshell> List<String> ell = new ArrayList<>();
ell ==> []

jshell> ell.add("a");
$10 ==> true

jshell> ell.add("b");
$11 ==> true

jshell> ell.add("z")
$12 ==> true

jshell> ell.add("y");
$13 ==> true

jshell> ell
ell ==> [a, b, z, y]

jshell> Collections.sort(ell);

jshell> ell
ell ==> [a, b, y, z]

jshell> ell
ell ==> [a, b, y, z]

jshell> ell = new LinkedList<>());
|  Error:
|  ';' expected
|  ell = new LinkedList<>());
|                          ^

jshell> ell = new LinkedList<>();
ell ==> []

jshell> ell.add("a")
$19 ==> true

jshell> ell.add("b");
$20 ==> true

jshell> ell.add("c");
$21 ==> true

jshell> ell
ell ==> [a, b, c]

jshell> Collections.sort(ell);

jshell> Map<String, Integer> m = new TreeMap<>();
m ==> {}

jshell> m.put("cats", 5);
$25 ==> null

jshell> m
m ==> {cats=5}

jshell> m.put("dogs", 10);
$27 ==> null

jshell> m.put("elephants", 1);
$28 ==> null

jshell> m
m ==> {cats=5, dogs=10, elephants=1}

jshell> m.get("cats")
$30 ==> 5

jshell> m.set("cats", 13);
|  Error:
|  cannot find symbol
|    symbol:   method set(java.lang.String,int)
|  m.set("cats", 13);
|  ^---^

jshell> m.put("cats", 13);
$31 ==> 5

jshell> m.put("cats", m.get("cats") + 10);
$32 ==> 13

jshell> m
m ==> {cats=23, dogs=10, elephants=1}

jshell> Map<Shape, Integer> s = new HashMap<>(); 
s ==> {}

jshell> s.put(new Rectangle(1,1), 3);
$35 ==> null

jshell> s
s ==> {Rectangle@6e2c634b=3}

jshell> s.put(new Circle(1,1), 3);
|  Error:
|  constructor Circle in class Circle cannot be applied to given types;
|    required: double
|    found:    int,int
|    reason: actual and formal argument lists differ in length
|  s.put(new Circle(1,1), 3);
|        ^-------------^

jshell> /open Circle.java

jshell> s.put(new Circle(1), 3);
$38 ==> null

jshell> s
s ==> {Circle@7c3df479=3, Rectangle@6e2c634b=3}

jshell> /exit
|  Goodbye
MAC:Mon Oct 25:10:25:interfaces>