added code for https://jstobigdata.com/spring/spring-bean-definition-inheritance/

Author: Bikraji

spring-core-ioc/src/main/java/basic/ioc/config/inheritance/Author.java

@@ -0,0 +1,33 @@
+package basic.ioc.config.inheritance;
+
+import java.util.StringJoiner;
+
+public abstract class Author {
+
+  private String name;
+  private Integer age;
+
+  public String getName() {
+    return name;
+  }
+
+  public void setName(String name) {
+    this.name = name;
+  }
+
+  public Integer getAge() {
+    return age;
+  }
+
+  public void setAge(Integer age) {
+    this.age = age;
+  }
+
+  @Override
+  public String toString() {
+    return new StringJoiner(", ", Author.class.getSimpleName() + "[", "]")
+        .add("name='" + name + "'")
+        .add("age=" + age)
+        .toString();
+  }
+}

spring-core-ioc/src/main/java/basic/ioc/config/inheritance/BookAuthor.java

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+package basic.ioc.config.inheritance;
+
+import java.util.StringJoiner;
+
+public class BookAuthor extends Author {
+
+  private String bookName;
+
+  public String getBookName() {
+    return bookName;
+  }
+
+  public void setBookName(String bookName) {
+    this.bookName = bookName;
+  }
+
+  @Override
+  public String toString() {
+    return new StringJoiner(", ", BookAuthor.class.getSimpleName() + "[", "]")
+        .add(super.toString())
+        .toString();
+  }
+}

spring-core-ioc/src/main/resources/basic.ioc.bean-config.inheritance.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<beans xmlns="http://www.springframework.org/schema/beans"
+       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+       xsi:schemaLocation="http://www.springframework.org/schema/beans
+        http://www.springframework.org/schema/beans/spring-beans.xsd">
+
+<bean id="abstractAuthor" abstract="true"
+      class="basic.ioc.config.inheritance.Author">
+  <property name="name" value="author"/>
+  <property name="age" value="18"/>
+</bean>
+
+<bean id="bookAuthor" parent="abstractAuthor"
+      class="basic.ioc.config.inheritance.BookAuthor">
+  <!-- override - age -->
+  <property name="age" value="20"/>
+  <property name="bookName" value="The Book"/>
+</bean>
+
+</beans>

spring-core-ioc/src/test/java/basic/ioc/config/inheritance/TestConfigInheritance.java

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+package basic.ioc.config.inheritance;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.support.ClassPathXmlApplicationContext;
+
+public class TestConfigInheritance {
+
+  @Test
+  public void testBeanConfigInheritance(){
+  ApplicationContext aContext
+      = new ClassPathXmlApplicationContext("basic.ioc.bean-config.inheritance.xml");
+
+  Author author = aContext.getBean(Author.class);
+  BookAuthor bookAuthor = aContext.getBean(BookAuthor.class);
+  System.out.println(author);
+  System.out.println(bookAuthor);
+  }
+}