ResilientSpring · ResilientSpring · Sep 9, 2021 · Sep 9, 2021 · Sep 9, 2021 · Sep 9, 2021
diff --git a/Oracle_Java_Tutorials/Abstract_Methods_and_Classes/Abstract_classes.java b/Oracle_Java_Tutorials/Abstract_Methods_and_Classes/Abstract_classes.java
@@ -0,0 +1,16 @@
+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.
+
+	// 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
@@ -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);
+
+}
diff --git a/Oracle_Java_Tutorials/Classes_and_Objects/Exercise2.java 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);
+
+	}
+
+}
diff --git a/Oracle_Java_Tutorials/Classes_and_Objects/Question1.java 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);
+
+	}
+
+}
diff --git a/Oracle_Java_Tutorials/Inheritance/Question1.java 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 {
+
+}
diff --git a/Oracle_Java_Tutorials/Inheritance/Writing_final_classes_and_methods6.java 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
@@ -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);
+
+	}
+
+}