Parvin Etibarli Java

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1. Ilkin olaraq ConfigurationController controllerinin ne ish gorduyunu arashdiririq: package com.azercell.paycell.paycellconsumer.controller; import com.azercell.paycell.paycellconsumer.model.ShortNumberConfiguration; import com.azercell.paycell.paycellconsumer.model.dto.ShortNumberConfigurationResponseDto; import com.azercell.paycell.paycellconsumer.service.ShortNumberConfigurationService; import io.swagger.v3.oas.annotations. Operation ; import io.swagger.v3.oas.annotations.tags. Tag ; import lombok. RequiredArgsConstructor ; import org.springframework.web.bind.annotation. GetMapping ; import org.springframework.web.bind.annotation. RequestMapping ; import org.springframework.web.bind.annotation. RestController ; import java.util.List; import java.util.stream.Collectors; @RestController @RequiredArgsConstructor @Tag (name = "ConfigurationController" ) @RequestMapping ( "/configurations" ) public class ConfigurationController { private final ShortNumberConfigu...

1. Spring Data JPA-da (Hibernate) default fetch strategiyaları Hibernate (və deməli Spring Boot da) hər ilişki ( relationship ) üçün default fetch type təyin edir. Əgər sən fetch parametrini açıq yazmasan, bunlar avtomatik olur: @ManyToOne → FetchType.EAGER @OneToOne → FetchType.EAGER @OneToMany → FetchType.LAZY @ManyToMany → FetchType.LAZY Spring Boot (Hibernate) da @ManyToOne və @OneToOne relationship-lər default olaraq eager , @OneToMany və @ManyToMany isə default olaraq lazy yüklənir. 

package az.etibarli.cascadetypes.entity; import jakarta.persistence. Entity ; import jakarta.persistence. GeneratedValue ; import jakarta.persistence.GenerationType; import jakarta.persistence. Id ; import jakarta.persistence. JoinColumn ; import jakarta.persistence. ManyToOne ; import lombok. Data ; @Data @Entity public class Address { @Id @GeneratedValue (strategy = GenerationType. IDENTITY ) private Long id ; private String city ; private String state ; private String zipCode ; @ManyToOne @JoinColumn (name = "customer_id" ) private Customer customer ; }   package az.etibarli.cascadetypes.entity; import jakarta.persistence. Entity ; import jakarta.persistence. GeneratedValue ; import jakarta.persistence.GenerationType; import jakarta.persistence. Id ; import jakarta.persistence. OneToMany ; import lombok. Data ; import java.util.LinkedHashSet; import java.util.List; import java.util.Set; @Data @Entity public class Customer { @Id @...

package az.kapitalbank.atlas.incoming.transfer.handler.service; import static az.kapitalbank.atlas.incoming.transfer.handler.config.properties.ApplicationConstants. MX ; import static java.time.LocalTime. now ; import az.kapitalbank.atlas.incoming.transfer.handler.domain.IncomingTransferProcessLog; import az.kapitalbank.atlas.incoming.transfer.handler.domain.MT103IncomingTransfer; import az.kapitalbank.atlas.incoming.transfer.handler.domain.ProcessStep; import az.kapitalbank.atlas.incoming.transfer.handler.util.SwiftMessageUtil; import az.kapitalbank.atlas.incoming.transfer.handler.util.XmlUtil; import java.util.List; import lombok. RequiredArgsConstructor ; import lombok.extern.slf4j. Slf4j ; import org.springframework.scheduling.annotation. Scheduled ; import org.springframework.stereotype. Service ; @Slf4j @Service @RequiredArgsConstructor public class TransferRetryScheduler { private final MT103Service mt103Service ; private final StepLoggerService stepLoggerService ; p...

+1. JVM memory areas. Thread safe memory areas, Garbage collector working principle, Java reference types +2. SOLID +3. Collection API: How does HashMap work under the hood, hash collision, Concurrent HashMap +4. Equals and HashCode contract -5. Thread, Volatile vs Synchronized, atomic variables(CAS-compare and swap). How to prevent deadlock. Deadlock vs livelock. Reentrant lock. +6. Error vs Exception +7. Immutable class(how to make object properties immutable, immutable collections) +8. DB index type(clustered, non clustered, composite) +9. DB normalization and denormalization +10. RDBMS vs non RDBMS +11. ACID vs BASE. Lock mechanism +12. Hash eviction policy(TTL, LRU, FIFO, LFU, MRU, random replacement, ARC). Problem: we have 2GB memory, how to store 15GB data in this cache +13. entity lifecycle +14. dirty check, flush +15. cascade types +16. n+1 problem (entity graph, join fetch) +17. lazy initialization exception 18. idempotency, safe in rest methods +19. IOC, DI, Proxy +20. AOP(c...