[BAEL-5406] IncompatibleClassChange Error (#16786)

* [BAEL-5406] IncompatibleClassChange Error

* [BAEL-5406] IncompatibleClassChange Error

* [BAEL-5406] IncompatibleClassChange Error

* [BAEL-5406] IncompatibleClassChange Error

* [BAEL-5406] IncompatibleClassChange Error

* [BAEL-5406] IncompatibleClassChange Error

* [BAEL-5406] IncompatibleClassChange Error Review comments

* [BAEL-5406] IncompatibleClassChange Error Review comments

* [BAEL-5406] IncompatibleClassChange Error Review comments

* [BAEL-5406] IncompatibleClassChange Error Review comments

Author: bhaskar16

libraries-bytecode/pom.xml

@@ -1,7 +1,7 @@
 <?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">
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xmlns="http://maven.apache.org/POM/4.0.0"
+         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>
     <artifactId>libraries-bytecode</artifactId>
     <version>0.0.1-SNAPSHOT</version>
@@ -40,6 +40,28 @@
             <artifactId>asm-util</artifactId>
             <version>${asm.version}</version>
         </dependency>
+        <!--
+                Importing the libraries as jars using system path. These are two versions of the same library, which is generated
+        from the code inside /incompatibleclasschange/libraries/modified and /incompatibleclasschange/libraries/original
+
+        To simulate the incompatible class change error, build the jars from the above-mentioned paths, place them in the locations mentioned in
+        the systemPath property and uncomment the following lines.
+
+               -->
+        <!--<dependency>
+            <groupId>org.dinosaur</groupId>
+            <artifactId>dinosaur</artifactId>
+            <version>1</version>
+            <scope>system</scope>
+            <systemPath>${project.basedir}/src/main/resources/dinosaur-1.jar</systemPath>
+        </dependency>
+        <dependency>
+            <groupId>org.dinosaur</groupId>
+            <artifactId>dinosaur</artifactId>
+            <version>2</version>
+            <scope>system</scope>
+            <systemPath>${project.basedir}/src/main/resources/dinosaur-2.jar</systemPath>
+        </dependency>-->
     </dependencies>
 
     <build>

libraries-bytecode/src/main/java/com/baeldung/incompatibleclasschange/libraries/modified/Dinosaur.java

@@ -0,0 +1,17 @@
+package com.baeldung.incompatibleclasschange.libraries.modified;
+
+public class Dinosaur {
+
+    /**
+     * This is the modified version of the library where the species() method is made static.
+     * The original version of the same hierarchy is not static.
+     *
+     */
+    public static void species(String sp) {
+        if (sp == null) {
+            System.out.println("I am a generic Dinosaur");
+        } else {
+            System.out.println(sp);
+        }
+    }
+}

libraries-bytecode/src/main/java/com/baeldung/incompatibleclasschange/libraries/original/Coelophysis.java

@@ -0,0 +1,12 @@
+package com.baeldung.incompatibleclasschange.libraries.original;
+
+public class Coelophysis extends Dinosaur {
+    public void mySpecies() {
+        species("My species is Coelophysis of the Triassic Period");
+    }
+
+    public static void main(String[] args) {
+        Coelophysis coelophysis = new Coelophysis();
+        coelophysis.mySpecies();
+    }
+}

libraries-bytecode/src/main/java/com/baeldung/incompatibleclasschange/libraries/original/Dinosaur.java

@@ -0,0 +1,11 @@
+package com.baeldung.incompatibleclasschange.libraries.original;
+
+public class Dinosaur {
+    public void species(String sp) {
+        if (sp == null) {
+            System.out.println("I am a generic Dinosaur");
+        } else {
+            System.out.println(sp);
+        }
+    }
+}