Improvement to code performance

.idea/.gitignore

.idea/artifacts/group_6_client_project_2023_jar.xml

.idea/checkstyle-idea.xml

.idea/compiler.xml

.idea/dataSources.xml

.idea/gradle.xml

.idea/group-6-client-project-2023.iml

.idea/jarRepositories.xml

.idea/misc.xml

.idea/modules.xml

.idea/modules/cms.main.iml

.idea/vcs.xml

cms/Config/ CacheConfig.java

cms/build.gradle

cms/src/main/java/com/project/cms/CmsApplication.java

.../java/com/project/cms/complaint/ComplaintServiceImpl.java

cms/src/main/resources/META-INF/MANIFEST.MF

cms/src/main/resources/application.properties

cms/src/main/resources/ehcache.xml

.../test/java/com/project/cms/staff/StaffControllerTest.java