From ab78714d85fbe3af32e4748f2de96d2d65fbbaa3 Mon Sep 17 00:00:00 2001 From: Ceiling_roof <48134466+ResilientSpring@users.noreply.github.com> Date: Thu, 9 Sep 2021 12:25:16 +0800 Subject: [PATCH 1/6] Committed 2021/09/09 --- .../Writing_final_classes_and_methods6.java | 20 +++++++++++++ .../Writing_final_classes_and_methods7.java | 28 +++++++++++++++++++ 2 files changed, 48 insertions(+) create mode 100644 Oracle_Java_Tutorials/Inheritance/Writing_final_classes_and_methods6.java create mode 100644 Oracle_Java_Tutorials/Inheritance/Writing_final_classes_and_methods7.java diff --git a/Oracle_Java_Tutorials/Inheritance/Writing_final_classes_and_methods6.java b/Oracle_Java_Tutorials/Inheritance/Writing_final_classes_and_methods6.java new file mode 100644 index 0000000..81a7627 --- /dev/null +++ b/Oracle_Java_Tutorials/Inheritance/Writing_final_classes_and_methods6.java @@ -0,0 +1,20 @@ +package Inheritance; + +class ChessAlgorithm__{ + enum ChessPlayer{ + BLACK, WHITE + } + + final ChessPlayer getFirstPlayer() { + return ChessPlayer.BLACK; + } +} + +public class Writing_final_classes_and_methods6 { + + public static void main(String[] args) { + // TODO Auto-generated method stub + + } + +} diff --git a/Oracle_Java_Tutorials/Inheritance/Writing_final_classes_and_methods7.java b/Oracle_Java_Tutorials/Inheritance/Writing_final_classes_and_methods7.java new file mode 100644 index 0000000..a066c73 --- /dev/null +++ b/Oracle_Java_Tutorials/Inheritance/Writing_final_classes_and_methods7.java @@ -0,0 +1,28 @@ +package Inheritance; + +import Inheritance.ChessAlgorithm___.ChessPlayer; + +class ChessAlgorithm___{ + enum ChessPlayer{ + BLACK, WHITE + } + + final ChessPlayer getFirstPlayer() { + return ChessPlayer.BLACK; + } +} + +public class Writing_final_classes_and_methods7 { + + public static void main(String[] args) { + // TODO Auto-generated method stub + + ChessAlgorithm___ returnType = new ChessAlgorithm___(); + + ChessPlayer symposiumChessPlayer = returnType.getFirstPlayer(); + + System.out.println(symposiumChessPlayer); + + } + +} From 66f5c333d41a004f71a3bc32d49af27c971936cf Mon Sep 17 00:00:00 2001 From: Ceiling_roof <48134466+ResilientSpring@users.noreply.github.com> Date: Thu, 9 Sep 2021 12:40:01 +0800 Subject: [PATCH 2/6] Committed 2021/09/09 --- .../Classes_and_Objects/Question1.java | 29 +++++++++++++++++++ 1 file changed, 29 insertions(+) create mode 100644 Oracle_Java_Tutorials/Classes_and_Objects/Question1.java diff --git a/Oracle_Java_Tutorials/Classes_and_Objects/Question1.java b/Oracle_Java_Tutorials/Classes_and_Objects/Question1.java new file mode 100644 index 0000000..13b8c4f --- /dev/null +++ b/Oracle_Java_Tutorials/Classes_and_Objects/Question1.java @@ -0,0 +1,29 @@ +package Classes_and_Objects; + +class IdentifyMyParts { + public static int x = 7; // class variable. + public int y = 3; // instance variable. +} + +public class Question1 { + + public static void main(String[] args) { + // TODO Auto-generated method stub + IdentifyMyParts a = new IdentifyMyParts(); + IdentifyMyParts b = new IdentifyMyParts(); + + a.y = 5; + b.y = 6; + + a.x = 1; + b.x = 2; + + System.out.println("a.y = " + a.y); + System.out.println("b.y = " + b.y); + System.out.println("a.x = " + a.x); + System.out.println("b.x = " + b.x); + System.out.println("IdentifyMyParts.x = " + IdentifyMyParts.x); + + } + +} From 1d73ef74d26ea5863dcb2462e4289af7f74e0db6 Mon Sep 17 00:00:00 2001 From: Ceiling_roof <48134466+ResilientSpring@users.noreply.github.com> Date: Thu, 9 Sep 2021 12:56:55 +0800 Subject: [PATCH 3/6] Committed 2021/09/09 --- .../Classes_and_Objects/Exercise2.java | 26 +++++++++++++++++++ 1 file changed, 26 insertions(+) create mode 100644 Oracle_Java_Tutorials/Classes_and_Objects/Exercise2.java diff --git a/Oracle_Java_Tutorials/Classes_and_Objects/Exercise2.java b/Oracle_Java_Tutorials/Classes_and_Objects/Exercise2.java new file mode 100644 index 0000000..f472ecc --- /dev/null +++ b/Oracle_Java_Tutorials/Classes_and_Objects/Exercise2.java @@ -0,0 +1,26 @@ +package Classes_and_Objects; + +class NumberHolder { + public int anInt; + public float aFloat; + + public NumberHolder(int a, float b) { + anInt = a; + aFloat = b; + } +} + +public class Exercise2 { + + public static void main(String[] args) { + // TODO Auto-generated method stub + + NumberHolder symposiumNumberHolder = new NumberHolder(1, 2); + + System.out.println(symposiumNumberHolder.anInt + symposiumNumberHolder.aFloat); + + System.out.println(symposiumNumberHolder.anInt + ", " + symposiumNumberHolder.aFloat); + + } + +} From 12d982b325edf9ccc1ad0e0ef87512a11f57b19a Mon Sep 17 00:00:00 2001 From: Ceiling_roof <48134466+ResilientSpring@users.noreply.github.com> Date: Thu, 9 Sep 2021 13:19:50 +0800 Subject: [PATCH 4/6] Committed 2021/09/09 --- .../Inheritance/Question1.java | 43 +++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 Oracle_Java_Tutorials/Inheritance/Question1.java diff --git a/Oracle_Java_Tutorials/Inheritance/Question1.java b/Oracle_Java_Tutorials/Inheritance/Question1.java new file mode 100644 index 0000000..f503d19 --- /dev/null +++ b/Oracle_Java_Tutorials/Inheritance/Question1.java @@ -0,0 +1,43 @@ +package Inheritance; + +class ClassA { + + public void methodOne(int i) { + + } + + public void methodTwo(int i) { + + } + + public static void methodThree(int i) { + + } + + public static void methodFour(int i) { + + } +} + +class ClassB extends ClassA { + + public static void methodOne(int i) { + + } + + public void methodTwo(int i) { + + } + + public void methodThree(int i) { + + } + + public static void methodFour(int i) { + + } +} + +public class Question1 { + +} From f579a116c449838b753d785ae68fdec554742fa2 Mon Sep 17 00:00:00 2001 From: Ceiling_roof <48134466+ResilientSpring@users.noreply.github.com> Date: Thu, 9 Sep 2021 13:36:54 +0800 Subject: [PATCH 5/6] Committed 2021/09/09 --- .../Abstract_classes.java | 13 +++++++++++++ 1 file changed, 13 insertions(+) create mode 100644 Oracle_Java_Tutorials/Abstract_Methods_and_Classes/Abstract_classes.java diff --git a/Oracle_Java_Tutorials/Abstract_Methods_and_Classes/Abstract_classes.java b/Oracle_Java_Tutorials/Abstract_Methods_and_Classes/Abstract_classes.java new file mode 100644 index 0000000..6107d31 --- /dev/null +++ b/Oracle_Java_Tutorials/Abstract_Methods_and_Classes/Abstract_classes.java @@ -0,0 +1,13 @@ +package Abstract_Methods_and_Classes; + +public class Abstract_classes { + + // An abstract class is a class that is declared "abstract"—it may or may not include abstract methods. + + // Abstract classes cannot be instantiated, but they can be subclassed. + + // When an abstract class is subclassed, + // the subclass usually provides implementations for all of the abstract methods in its parent class. + // However, if it does not, then the subclass must also be declared abstract. + +} From 0c4299646fcbac19b61b13d661cb4c72e789ab24 Mon Sep 17 00:00:00 2001 From: Ceiling_roof <48134466+ResilientSpring@users.noreply.github.com> Date: Thu, 9 Sep 2021 13:48:08 +0800 Subject: [PATCH 6/6] Committed 2021/09/09 --- .../Abstract_Methods_and_Classes/Abstract_classes.java | 3 +++ .../Abstract_Methods_and_Classes/Abstract_methods.java | 9 +++++++++ 2 files changed, 12 insertions(+) create mode 100644 Oracle_Java_Tutorials/Abstract_Methods_and_Classes/Abstract_methods.java diff --git a/Oracle_Java_Tutorials/Abstract_Methods_and_Classes/Abstract_classes.java b/Oracle_Java_Tutorials/Abstract_Methods_and_Classes/Abstract_classes.java index 6107d31..e013b3b 100644 --- a/Oracle_Java_Tutorials/Abstract_Methods_and_Classes/Abstract_classes.java +++ b/Oracle_Java_Tutorials/Abstract_Methods_and_Classes/Abstract_classes.java @@ -9,5 +9,8 @@ public class Abstract_classes { // When an abstract class is subclassed, // the subclass usually provides implementations for all of the abstract methods in its parent class. // However, if it does not, then the subclass must also be declared abstract. + + // Reference: + // https://docs.oracle.com/javase/tutorial/java/IandI/abstract.html } diff --git a/Oracle_Java_Tutorials/Abstract_Methods_and_Classes/Abstract_methods.java b/Oracle_Java_Tutorials/Abstract_Methods_and_Classes/Abstract_methods.java new file mode 100644 index 0000000..b9e69f5 --- /dev/null +++ b/Oracle_Java_Tutorials/Abstract_Methods_and_Classes/Abstract_methods.java @@ -0,0 +1,9 @@ +package Abstract_Methods_and_Classes; + +public abstract class Abstract_methods { + + // An abstract method is a method that is declared without an implementation (without braces, + // and followed by a semicolon), like this: + abstract void moveTo(double deltaX, double deltaY); + +}