Initial Commit (#142)

* Initial Commit

Added Maven Annotation Processor Demo project. Initial commit.

* Test - checking

* Delete test.rtf

* Initial commits

Initial commits for sample code

* Update SuppressWarningsDemo.java

* Code changes till SafeVarargs

Code changes till SafeVarargs

* Completed source code

Completed source code

* Final draft

Final draft version. Grammarly check done.

* Deleted java docs

Deleted java docs

core-java/annotation-processing/introduction-to-annotations/annotations-demo/pom.xml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>org.example</groupId>
+    <artifactId>annotations-demo</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <properties>
+        <maven.compiler.source>11</maven.compiler.source>
+        <maven.compiler.target>11</maven.compiler.target>
+    </properties>
+
+</project>

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/AnnotatedMethods.java

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+package com.reflectoring;
+
+public class AnnotatedMethods {
+
+    @Test
+    public void Test_1() {
+
+        System.out.println("This is the first test");
+    }
+
+    public void Test_2() {
+
+        System.out.println("This is the second test");
+    }
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/BasicAnnotationTest.java

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+package com.reflectoring;
+
+public class BasicAnnotationTest {
+
+    public static void main(String[] args) {
+
+    }
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/ClassRetention.java

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+package com.reflectoring;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.CLASS)
+public @interface ClassRetention {
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/Company.java

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+package com.reflectoring;
+
+import java.lang.annotation.*;
+
+@Inherited
+@Documented
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface Company{
+    String name() default "ABC";
+    String city() default "XYZ";
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/CustomAnnotatedEmployee.java

@@ -0,0 +1,19 @@
+package com.reflectoring;
+
+@Company
+public class CustomAnnotatedEmployee {
+
+    private int id;
+    private String name;
+
+    public CustomAnnotatedEmployee(int id, String name) {
+        this.id = id;
+        this.name = name;
+    }
+
+    public void getEmployeeDetails(){
+
+        System.out.println("Employee Id: " + id);
+        System.out.println("Employee Name: " + name);
+    }
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/CustomAnnotatedManager.java

@@ -0,0 +1,8 @@
+package com.reflectoring;
+
+public class CustomAnnotatedManager extends CustomAnnotatedEmployee{
+
+    public CustomAnnotatedManager(int id, String name) {
+        super(id, name);
+    }
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/DeprecatedDemo.java

@@ -0,0 +1,10 @@
+package com.reflectoring;
+
+public class DeprecatedDemo {
+
+    @Deprecated(since = "4.5", forRemoval = true)
+    public void testLegacyFunction() {
+
+        System.out.println("This is a legacy function");
+    }
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/DeprecatedDemoTest.java

@@ -0,0 +1,10 @@
+package com.reflectoring;
+
+public class DeprecatedDemoTest {
+
+    public static void main(String[] args) {
+
+        DeprecatedDemo demo = new DeprecatedDemo();
+        demo.testLegacyFunction();
+    }
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/Employee.java

@@ -0,0 +1,10 @@
+package com.reflectoring;
+
+@Company
+public class Employee {
+
+    public void getEmployeeStatus(){
+
+        System.out.println("This is the Base Employee class");
+    }
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/EmployeeRetentionAnnotation.java

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+package com.reflectoring;
+
+@SourceRetention
+@RuntimeRetention
+@ClassRetention
+public class EmployeeRetentionAnnotation {
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/FunctionalInterfaceTest.java

@@ -0,0 +1,15 @@
+package com.reflectoring;
+
+@FunctionalInterface
+interface Print {
+    void printString(String testString);
+}
+
+public class FunctionalInterfaceTest {
+
+    public static void main(String args[]) {
+
+        Print testPrint = (String testString) -> System.out.println(testString);
+        testPrint.printString("This is a String");
+    }
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/Manager.java

@@ -0,0 +1,10 @@
+package com.reflectoring;
+
+public class Manager extends Employee {
+
+    @Override
+    public void getEmployeeStatus(){
+
+        System.out.println("This is the Manager class");
+    }
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/MultiValueAnnotatedEmployee.java

@@ -0,0 +1,6 @@
+package com.reflectoring;
+
+@Company(name = "AAA", city = "ZZZ")
+public class MultiValueAnnotatedEmployee {
+
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/OverrideTest.java

@@ -0,0 +1,10 @@
+package com.reflectoring;
+
+public class OverrideTest {
+
+    public static void main(String[] args) {
+
+        Manager manager = new Manager();
+        manager.getEmployeeStatus();
+    }
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/RepeatableCompanies.java

@@ -0,0 +1,9 @@
+package com.reflectoring;
+
+import java.lang.annotation.*;
+
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface RepeatableCompanies {
+    RepeatableCompany[] value() default{};
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/RepeatableCompany.java

@@ -0,0 +1,11 @@
+package com.reflectoring;
+
+import java.lang.annotation.*;
+
+@Target(ElementType.TYPE)
+@Repeatable(RepeatableCompanies.class)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface RepeatableCompany {
+    String name() default "Name_1";
+    String city() default "City_1";
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/RepeatedAnnotatedEmployee.java

@@ -0,0 +1,6 @@
+package com.reflectoring;
+
+@RepeatableCompany
+@RepeatableCompany(name =  "Name_2", city = "City_2")
+public class RepeatedAnnotatedEmployee {
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/RetentionTest.java

@@ -0,0 +1,16 @@
+package com.reflectoring;
+
+public class RetentionTest {
+
+    public static void main(String[] args) {
+
+        SourceRetention[] sourceRetention = new EmployeeRetentionAnnotation().getClass().getAnnotationsByType(SourceRetention.class);
+        System.out.println("Source Retentions at run-time: " + sourceRetention.length);
+
+        RuntimeRetention[] runtimeRetention = new EmployeeRetentionAnnotation().getClass().getAnnotationsByType(RuntimeRetention.class);
+        System.out.println("Run-time Retentions at run-time: " + runtimeRetention.length);
+
+        ClassRetention[] classRetention = new EmployeeRetentionAnnotation().getClass().getAnnotationsByType(ClassRetention.class);
+        System.out.println("Class Retentions at run-time: " + classRetention.length);
+    }
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/RuntimeRetention.java

@@ -0,0 +1,11 @@
+package com.reflectoring;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface RuntimeRetention {
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/SafeVarargsTest.java

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+package com.reflectoring;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class SafeVarargsTest {
+
+    private void printString(String test1) {
+
+        System.out.println(test1);
+    }
+
+    private void printString(String test1, String test2) {
+
+        System.out.println(test1);
+        System.out.println(test2);
+    }
+
+    private void printStringVarargs(String... tests) {
+
+        for (String test : tests) {
+
+            System.out.println(test);
+        }
+    }
+
+    @SafeVarargs
+    private void printStringSafeVarargs(List<String>... testStringLists) {
+
+        for (List<String> testStringList : testStringLists) {
+
+            for (String testString : testStringList) {
+
+                System.out.println(testString);
+            }
+        }
+    }
+
+    public static void main(String[] args) {
+
+        SafeVarargsTest test = new SafeVarargsTest();
+
+        test.printString("String1");
+        test.printString("*******");
+
+        test.printString("String1", "String2");
+        test.printString("*******");
+
+        test.printStringVarargs("String1", "String2");
+        test.printString("*******");
+
+        List<String> testStringList1 = Arrays.asList("One", "Two");
+        List<String> testStringList2 = Arrays.asList("Three", "Four");
+
+        test.printStringSafeVarargs(testStringList1, testStringList2);
+    }
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/SingleValueAnnotatedEmployee.java

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+package com.reflectoring;
+
+@SingleValueAnnotationCompany("XYZ")
+public class SingleValueAnnotatedEmployee {
+
+    private int id;
+    private String name;
+
+    public SingleValueAnnotatedEmployee(int id, String name) {
+        this.id = id;
+        this.name = name;
+    }
+
+    public void getEmployeeDetails(){
+
+        System.out.println("Employee Id: " + id);
+        System.out.println("Employee Name: " + name);
+    }
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/SingleValueAnnotationCompany.java

@@ -0,0 +1,9 @@
+package com.reflectoring;
+
+import java.lang.annotation.*;
+
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface SingleValueAnnotationCompany {
+    String value() default "ABC";
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/SourceRetention.java

@@ -0,0 +1,8 @@
+package com.reflectoring;
+
+import java.lang.annotation.*;
+
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.SOURCE)
+public @interface SourceRetention {
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/SuppressWarningsDemo.java

@@ -0,0 +1,22 @@
+package com.reflectoring;
+
+import java.util.HashMap;
+import java.util.Map;
+
+@SuppressWarnings({"rawtypes", "unchecked"})
+public class SuppressWarningsDemo {
+
+    public static void main(String[] args) {
+
+        SuppressWarningsDemo swDemo = new SuppressWarningsDemo();
+        swDemo.testSuppressWarning();
+    }
+
+    public void testSuppressWarning() {
+
+        Map testMap = new HashMap();
+        testMap.put(1, "Item_1");
+        testMap.put(2, "Item_2");
+        testMap.put(3, "Item_3");
+    }
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/Test.java

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+package com.reflectoring;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.METHOD)
+public @interface Test {
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/TestAnnotatedMethods.java

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+package com.reflectoring;
+
+import java.lang.annotation.Annotation;
+import java.lang.reflect.Method;
+
+public class TestAnnotatedMethods {
+
+    public static void main(String[] args) throws Exception {
+
+        Class<AnnotatedMethods> annotatedMethodsClass = AnnotatedMethods.class;
+
+        for (Method method : annotatedMethodsClass.getDeclaredMethods()) {
+
+            Annotation annotation = method.getAnnotation(Test.class);
+            Test test = (Test) annotation;
+
+            // If the annotation is not null
+            if (test != null) {
+
+                try {
+                    method.invoke(annotatedMethodsClass.getDeclaredConstructor().newInstance());
+                } catch (Throwable ex) {
+                    System.out.println(ex.getCause());
+                }
+
+            }
+        }
+    }
+}
+
+

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/TestCustomAnnotatedEmployee.java

@@ -0,0 +1,18 @@
+package com.reflectoring;
+
+import java.lang.annotation.Annotation;
+
+public class TestCustomAnnotatedEmployee {
+
+    public static void main(String[] args) {
+
+        CustomAnnotatedEmployee employee = new CustomAnnotatedEmployee(1, "John Doe");
+        employee.getEmployeeDetails();
+
+        Annotation companyAnnotation = employee.getClass().getAnnotation(Company.class);
+        Company company = (Company)companyAnnotation;
+
+        System.out.println("Company Name: " + company.name());
+        System.out.println("Company City: " + company.city());
+    }
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/TestCustomAnnotatedManager.java

@@ -0,0 +1,18 @@
+package com.reflectoring;
+
+import java.lang.annotation.Annotation;
+
+public class TestCustomAnnotatedManager {
+
+    public static void main(String[] args) {
+
+        CustomAnnotatedManager manager = new CustomAnnotatedManager(1, "John Doe");
+        manager.getEmployeeDetails();
+
+        Annotation companyAnnotation = manager.getClass().getAnnotation(Company.class);
+        Company company = (Company)companyAnnotation;
+
+        System.out.println("Company Name: " + company.name());
+        System.out.println("Company City: " + company.city());
+    }
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/TestMultiValueAnnotatedEmployee.java

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+package com.reflectoring;
+
+import java.lang.annotation.Annotation;
+
+public class TestMultiValueAnnotatedEmployee {
+
+    public static void main(String[] args) {
+
+        MultiValueAnnotatedEmployee employee = new MultiValueAnnotatedEmployee();
+
+        Annotation companyAnnotation = employee.getClass().getAnnotation(Company.class);
+        Company company = (Company)companyAnnotation;
+
+        System.out.println("Company Name: " + company.name());
+        System.out.println("Company City: " + company.city());
+    }
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/TestRepeatedAnnotation.java

@@ -0,0 +1,14 @@
+package com.reflectoring;
+
+public class TestRepeatedAnnotation {
+
+    public static void main(String[] args) {
+
+        RepeatableCompany[] repeatableCompanies = RepeatedAnnotatedEmployee.class.getAnnotationsByType(RepeatableCompany.class);
+        for (RepeatableCompany repeatableCompany : repeatableCompanies) {
+
+            System.out.println("Name: " + repeatableCompany.name());
+            System.out.println("City: " + repeatableCompany.city());
+        }
+    }
+}

core-java/annotation-processing/introduction-to-annotations/annotations-demo/src/main/java/com/reflectoring/TestSingleValueAnnotatedEmployee.java

@@ -0,0 +1,17 @@
+package com.reflectoring;
+
+import java.lang.annotation.Annotation;
+
+public class TestSingleValueAnnotatedEmployee {
+
+    public static void main(String[] args) {
+
+        SingleValueAnnotatedEmployee employee = new SingleValueAnnotatedEmployee(1, "John Doe");
+        employee.getEmployeeDetails();
+
+        Annotation companyAnnotation = employee.getClass().getAnnotation(SingleValueAnnotationCompany.class);
+        SingleValueAnnotationCompany company = (SingleValueAnnotationCompany)companyAnnotation;
+
+        System.out.println("Company Name: " + company.value());
+    }
+}