Added maven-checkstyle-plugin to parent POM for code style checks

- Integrate Checkstyle to enforce coding standards across modules.
- Ensure Checkstyle applies to both dmi-service and dmi-stub modules.
- Fixed all code check style issues.

Issue-ID: CPS-2461
Change-Id: Ie84928c1f2e3de549cc8fab2001974369884a831
Signed-off-by: sourabh_sourabh <sourabh.sourabh@est.tech>
diff --git a/pom.xml b/pom.xml
index b457e23..f8d34c5 100644
--- a/pom.xml
+++ b/pom.xml
@@ -1,3 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
 <!--
   ============LICENSE_START=======================================================
   Copyright (c) 2021-2024 Nordix Foundation.
@@ -18,6 +19,7 @@
   SPDX-License-Identifier: Apache-2.0
   ============LICENSE_END=========================================================
 -->
+
 <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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
@@ -43,4 +45,84 @@
     <name>ncmp-dmi-plugin</name>
     <description>DMI Plugin Service</description>
 
+    <properties>
+        <cps.version>3.5.2</cps.version>
+    </properties>
+
+    <build>
+        <plugins>
+            <!-- Add the Maven Checkstyle Plugin here -->
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-checkstyle-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <id>onap-license</id>
+                        <goals>
+                            <goal>check</goal>
+                        </goals>
+                        <phase>process-sources</phase>
+                        <configuration>
+                            <configLocation>onap-checkstyle/check-license.xml</configLocation>
+                            <includeResources>false</includeResources>
+                            <includeTestSourceDirectory>true</includeTestSourceDirectory>
+                            <includeTestResources>false</includeTestResources>
+                            <sourceDirectories>
+                                <sourceDirectory>${project.build.sourceDirectory}</sourceDirectory>
+                            </sourceDirectories>
+                            <consoleOutput>false</consoleOutput>
+                            <violationSeverity>warning</violationSeverity>
+                            <failOnViolation>true</failOnViolation>
+                        </configuration>
+                    </execution>
+                    <execution>
+                        <id>onap-java-style</id>
+                        <goals>
+                            <goal>check</goal>
+                        </goals>
+                        <phase>process-sources</phase>
+                        <configuration>
+                            <configLocation>onap-checkstyle/onap-java-style.xml</configLocation>
+                            <sourceDirectories>
+                                <sourceDirectory>${project.build.sourceDirectory}</sourceDirectory>
+                            </sourceDirectories>
+                            <includeResources>true</includeResources>
+                            <includeTestSourceDirectory>true</includeTestSourceDirectory>
+                            <includeTestResources>true</includeTestResources>
+                            <consoleOutput>false</consoleOutput>
+                            <violationSeverity>warning</violationSeverity>
+                            <failOnViolation>true</failOnViolation>
+                        </configuration>
+                    </execution>
+                    <execution>
+                        <id>cps-java-style</id>
+                        <goals>
+                            <goal>check</goal>
+                        </goals>
+                        <phase>process-sources</phase>
+                        <configuration>
+                            <configLocation>cps-java-style.xml</configLocation>
+                            <sourceDirectories>
+                                <sourceDirectory>${project.build.sourceDirectory}</sourceDirectory>
+                            </sourceDirectories>
+                            <includeResources>true</includeResources>
+                            <includeTestSourceDirectory>true</includeTestSourceDirectory>
+                            <includeTestResources>true</includeTestResources>
+                            <consoleOutput>true</consoleOutput>
+                            <violationSeverity>warning</violationSeverity>
+                            <failOnViolation>true</failOnViolation>
+                        </configuration>
+                    </execution>
+                </executions>
+                <dependencies>
+                    <dependency>
+                        <groupId>${project.groupId}</groupId>
+                        <artifactId>checkstyle</artifactId>
+                        <version>${cps.version}</version>
+                    </dependency>
+                </dependencies>
+            </plugin>
+        </plugins>
+    </build>
+
 </project>