java add programs - 4th Sep20

Motta Shiva · Motta Shiva · commit 7d1c7ee67345 · 2020-09-04T21:55:33.000+05:30
diff --git a/JavaBasicPrograms/src/main/java/learnAbstract/FinalExample.java b/JavaBasicPrograms/src/main/java/learnAbstract/FinalExample.java
@@ -0,0 +1,37 @@
+package learnAbstract;
+
+
+/*Refer the site for final keywords: https://beginnersbook.com/2014/07/final-keyword-java-final-variable-method-class/
+*/
+public class FinalExample {
+
+	final String place = "Chennai";
+	final int accNo;
+	final String rollNo;	
+	
+	
+	FinalExample(int aNum, String rNum) {  // initializing the final value in constructor by passing parameter variables
+		accNo = aNum;
+		rollNo = rNum;
+	}
+	
+	
+	void empData() {
+		System.out.println("Acc number is: "+accNo);
+		System.out.println("Emp roll number is: "+rollNo);
+	}
+	
+	void myPlace() {
+		System.out.println(place);
+	}
+	
+
+	public static void main(String[] args) {
+		FinalExample finalKey = new FinalExample(1234, "student1234");
+		finalKey.empData();
+		finalKey.myPlace();
+		/*finalKey.findPlaces();
+		finalKey.likePlace();*/		
+
+	}
+}
diff --git a/JavaBasicPrograms/src/main/java/learnAbstract/FinalKeywordExample.java b/JavaBasicPrograms/src/main/java/learnAbstract/FinalKeywordExample.java
@@ -0,0 +1,23 @@
+package learnAbstract;
+
+public class FinalKeywordExample {	
+	String name = "Charan";
+	final int i =20;
+	int j = 30;
+	
+//	public abstract void add();
+	
+	public void multiples(int i, int j) {
+				int product = i * j;
+		System.out.println("Product value is: "+product);
+	}
+	
+
+	public static void main(String[] args) {
+		FinalKeywordExample finalKey = new FinalKeywordExample();
+		finalKey.multiples(50, 40);  // need to check how come the final variable value is getting changed/updated.
+		
+
+	}
+
+}
diff --git a/JavaBasicPrograms/src/main/java/learnAbstract/InterfaceExample.java b/JavaBasicPrograms/src/main/java/learnAbstract/InterfaceExample.java
@@ -0,0 +1,15 @@
+package learnAbstract;
+
+public interface InterfaceExample {
+	
+	int num = 123;
+	String name = "aji";
+	int age = 35;
+	
+	void student();	
+	void employee();	
+	public void person_details();	
+
+}
+
+
diff --git a/JavaBasicPrograms/src/main/java/learnConstructors/ParameterizedConstructor.java b/JavaBasicPrograms/src/main/java/learnConstructors/ParameterizedConstructor.java
@@ -14,7 +14,7 @@ public class ParameterizedConstructor {
 
 
 	public void aboutAnimal() {
-		System.out.println("Animal Name is - "+animal_name+"; " + "Animal ID is - "+animal_id);
+		System.out.println("Animal Name is: " +animal_name +"; " +"Animal ID is - "+animal_id);
 	}
 
 	public static void main(String[] args) {
diff --git a/JavaBasicPrograms/src/main/java/learnFinalKeyword/FinalClassExample.java b/JavaBasicPrograms/src/main/java/learnFinalKeyword/FinalClassExample.java
@@ -0,0 +1,42 @@
+package learnFinalKeyword;
+
+final class FinalClassExample {
+
+	public void car() {
+		System.out.println("final class example with sample");
+	}
+
+	final void bike() {
+		System.out.println("Chekc for the final class functionality");
+	}
+
+	public static void main(String[] args) {
+		FinalClassExample fc = new FinalClassExample();
+		fc.car();
+		fc.bike();	 
+	}
+
+} 
+
+// cannot inherit the final class to any other sub class - compilation error will be thrown
+
+// class Test extends FinalClassExample {  //compilation error is thrown
+class Test {
+
+	void demoPrg() {
+		System.out.println("Check if we can inherit the 'final class' ");
+	}
+
+	void bike() {  // this method is not overridden as not able to inherit the final class
+		System.out.println("check for the overridden method");
+	}
+
+	public static void main(String[] args) {
+		Test test = new Test();
+		//	test.car();
+		test.bike();
+		test.demoPrg();
+
+	}
+
+}
diff --git a/JavaBasicPrograms/src/main/java/learnFinalKeyword/FinalKeywordExample.java b/JavaBasicPrograms/src/main/java/learnFinalKeyword/FinalKeywordExample.java
@@ -0,0 +1,36 @@
+package learnFinalKeyword;
+
+public class FinalKeywordExample {
+
+	final String place = "Chennai";
+	final int accNo = 4500;
+	final String rollNo;	
+
+	FinalKeywordExample() {  // initializing the final value in constructor 
+	//	accNo = 3000;  // final variable should be initialized either in class level or in constructor, Not in methods
+		rollNo = "abc123";
+	} 
+
+	public void findPlaces() {
+		String place = "Madurai";
+		System.out.println("New place name is: "+place);
+	}
+
+	public void accNumber() {
+//		accNo = 500;  // cannot change or modify the final value
+//		rollNo = "123edf";
+		System.out.println(accNo);
+		System.err.println(rollNo);
+	}
+
+	public static void main(String[] args) {
+		
+		FinalKeywordExample finalKey = new FinalKeywordExample();
+		finalKey.findPlaces();
+		finalKey.accNumber();
+		
+
+
+	}
+
+}
diff --git a/JavaBasicPrograms/src/main/java/learnFinalKeyword/FinalMethodExample.java b/JavaBasicPrograms/src/main/java/learnFinalKeyword/FinalMethodExample.java
@@ -0,0 +1,34 @@
+package learnFinalKeyword;
+
+class FinalMethodExample {
+	final int marks = 100;
+	
+	final void sample1() {
+		int marks = 150;
+		System.out.println("It is a final method - sample1");
+		System.out.println("Max marks is: "+marks);
+	}
+	
+	public void sample2() {
+		System.out.println("It is a sample 2 method");
+	}
+	
+}
+
+class FinalMethod extends FinalMethodExample {		
+	
+	/* void sample1() {     // we cannot inherit the final methods into other class
+		System.out.println("Method 2 new sample");
+	}*/
+	
+	public void sample2() {
+		System.out.println("Overrriding the method");
+	}	
+	
+	public static void main(String[] args) {
+		FinalMethod fm = new FinalMethod();
+		fm.sample1();
+		fm.sample2();		
+
+	}
+}
diff --git a/JavaBasicPrograms/src/main/java/learnFinalKeyword/FinalMethodExample2.java b/JavaBasicPrograms/src/main/java/learnFinalKeyword/FinalMethodExample2.java
@@ -0,0 +1,27 @@
+package learnFinalKeyword;
+
+public class FinalMethodExample2 extends FinalMethodExample {
+	
+	/*void sample1() {   // unable to override the final methods into other class
+		System.out.println("Trying to override the 'final' method from parent class");
+	}*/
+	
+	@Override
+	public void sample2() {
+		System.out.println("This is method is overridden from the parent class");
+		
+	}
+	
+	public void marks() {
+		System.out.println("Max Marks declared is: " +marks);
+	}
+	
+
+	public static void main(String[] args) {
+		FinalMethodExample2 fm2 = new FinalMethodExample2();
+		fm2.sample2();
+		fm2.sample1();	
+
+	}
+
+}
diff --git a/JavaBasicPrograms/src/main/java/learnMap/HashMapExample.java b/JavaBasicPrograms/src/main/java/learnMap/HashMapExample.java
@@ -0,0 +1,41 @@
+package learnMap;
+
+import java.util.HashMap;
+
+public class HashMapExample {
+
+	public static void main(String[] args) {
+
+		HashMap<Integer, String> employees = new HashMap<Integer, String>();
+
+		employees.put(101, "Rakesh");
+		employees.put(102, "Ramu");
+		employees.put(123, "Ajith");
+		employees.put(101, "Charan");
+		employees.put(null, "abcd");
+		employees.put(145, "Charan");
+		System.out.println("Employees details: " +employees);
+
+
+		HashMap<Integer, String> duplicate = new HashMap<Integer, String>();
+		duplicate.putAll(employees);
+		System.out.println(duplicate);
+
+		//clear all values in duplicate
+		duplicate.clear();
+		System.out.println(duplicate);
+
+		// check if a key present
+		System.out.println("Does it have 123 key? " +employees.containsKey(123));
+
+
+		// check if a key present
+		System.out.println("Does it have value Charan? " +employees.containsValue("Charan"));
+		
+		//clone the values
+		System.out.println("clone the values:" +employees.clone());
+
+
+	}
+
+}
diff --git a/JavaBasicPrograms/src/main/java/learnMap/TreeMapExample.java b/JavaBasicPrograms/src/main/java/learnMap/TreeMapExample.java
@@ -0,0 +1,24 @@
+package learnMap;
+
+import java.util.TreeMap;
+
+public class TreeMapExample {
+
+	public static void main(String[] args) {
+
+		TreeMap<String, String> places = new TreeMap<String, String>();
+		places.put("Gopalapuram", "Chennai"); // key -- value pair combination data
+		places.put("Guindy", "Chennai");
+		places.put("Royapet", "Chennai");
+		places.put("DMS", "Chennai");
+		places.put("Chennai", "Tambaram");
+		places.put("Chennai", "PVM");
+		places.put(null, "Chennai"); // null pointer exception will be thrown during runtime
+		
+		System.out.println(places);		
+		
+
+
+	}
+
+}
diff --git a/JavaBasicPrograms/src/main/java/learnPolymorphism/learnOverridingwithParametersChild.java b/JavaBasicPrograms/src/main/java/learnPolymorphism/learnOverridingwithParametersChild.java
@@ -0,0 +1,47 @@
+package learnPolymorphism;
+
+public class learnOverridingwithParametersChild extends learnOverridingwithParametersParent {
+
+	@Override
+	public void add(int i, int j) {
+		int sum = i +j;
+		System.out.println("Sum is:" +sum);
+	}
+
+	@Override
+	public void add(int i, long k) {  // can use the same method, same parameters and same implementation details
+		long sum = i + k;
+		System.out.println("Sum is long:" +sum);
+	}
+
+
+	public void add(int i, int j, int k) {  //this method won't be overridden as it has different parameters in child class
+		int sum = i +j + k;
+		System.out.println("Sum is:" +sum);
+	}
+
+
+	@Override
+	public void printName() {
+		System.out.println("Print child class statement");
+	}
+
+	
+	public void checkOverriding(String name) { // same method in parent class but different parameters - so NO overriding
+		System.out.println("Same Method used in parent class but without parameters" +name);
+	}
+
+
+	public static void main(String[] args) {
+
+		learnOverridingwithParametersChild child = new learnOverridingwithParametersChild(); // can use this object as well
+	//	learnOverridingwithParametersParent child = new learnOverridingwithParametersChild(); // dynamic polymorphism
+		child.add(200, 200200200);
+		child.add(10, 20, 30); // cannot execute this function if we use dynamic polymorphism as this method is not in parent class
+		child.printName();
+		child.checkOverriding("Charan");
+		child.checkOverriding(100); //this method is present/used in parent class (int number)
+
+	}
+
+}
diff --git a/JavaBasicPrograms/src/main/java/learnPolymorphism/learnOverridingwithParametersParent.java b/JavaBasicPrograms/src/main/java/learnPolymorphism/learnOverridingwithParametersParent.java
@@ -0,0 +1,50 @@
+package learnPolymorphism;
+
+public class learnOverridingwithParametersParent {
+	
+	/*int i = 10;
+	int j = 20;
+	long k = 400500600;
+	String name;*/
+	
+	public void add(int i, int j) {
+		int sum = i + j;
+		System.out.println("Sum value is in Integer: "+sum); 
+	}
+	
+	public void add(int i, long k) {
+		long sum = i + k;
+		System.out.println("Sum is long:" +sum);
+	}
+	
+	
+	public void printName(String name) {
+		System.out.println("Name is:" +name);		
+	}
+	
+	
+	public void printName() {
+		System.out.println("check for overrriding concept");
+	}
+	
+	public void checkOverriding() {
+		System.out.println("Check if the method is overriding");
+	}
+	
+	public void checkOverriding(int number) {
+		System.out.println("Check if the method is overriding in parent class: "+number);
+	}
+	
+
+	public static void main(String[] args) {
+		
+		learnOverridingwithParametersParent parent = new learnOverridingwithParametersParent();
+		parent.add(50, 40);
+		parent.printName("Ajeeth Kumar");
+//		parent.add(10, 20, 30);
+		parent.printName();
+		parent.checkOverriding(2500);
+		
+	}
+
+}
diff --git a/JavaBasicPrograms/src/main/java/learnString/StringExample.java b/JavaBasicPrograms/src/main/java/learnString/StringExample.java

Original file line number	Diff line number	Diff line change
`@@ -14,7 +14,7 @@ public class ParameterizedConstructor {`
`14`	`14`
`15`	`15`
`16`	`16`	`public void aboutAnimal() {`
`17`		`- System.out.println("Animal Name is - "+animal_name+"; " + "Animal ID is - "+animal_id);`
	`17`	`+ System.out.println("Animal Name is: " +animal_name +"; " +"Animal ID is - "+animal_id);`
`18`	`18`	`}`
`19`	`19`
`20`	`20`	`public static void main(String[] args) {`