Springboot fegin clent example

 https://www.javaguides.net/2022/10/spring-boot-microservices-communication-using-spring-cloud-open-feign.html

completeable future exception handling

 https://dzone.com/articles/exception-handling-in-java-completablefuture

Interview question Question prepare

 https://levelup.gitconnected.com/spring-springboot-interview-questions-series-1-cf059c0b9c64

https://medium.com/@AlexanderObregon/solving-5-common-java-interview-coding-problems-39560d92d0aa

 

https://medium.com/lunartechai/cracking-java-interview-bcc73fb75be9

 

https://medium.com/@saygiligozde/design-patterns-in-java-5251032ca244

 

https://news.lunartech.ai/cracking-java-interview-bcc73fb75be9   

Design pattern

 Design pattern 

Mainly there are three types of design pattern.

1.Creational.

2.Stractural

3.Behavioral

1.Creational Design pattern types:-

 1.singleton design :-

     Ways to create singleton object:-

    1.Egar singleton object creation:

    .Lazy singleton Object creation 

Docker tutorial

 

https://learndocker.online/courses/introduction/

 

 

JPA manyTo Mnay Entity mapping

 https://www.callicoder.com/hibernate-spring-boot-jpa-many-to-many-mapping-example/

package com.example.demo.hibernetexample.posttag.entity;

import jakarta.persistence.*;
import lombok.*;

import java.util.HashSet;
import java.util.Set;

@Entity
@Table(name = "post")
@NoArgsConstructor
@AllArgsConstructor
@Getter
@Setter
@Builder
@ToString
public class Post {
    @Id
    @GeneratedValue(strategy = jakarta.persistence.GenerationType.IDENTITY)
    @Column(name = "post_id")
    private Integer postId;
    @Column(name = "post_name")
    private String postName;
    @ManyToMany(cascade = { CascadeType.ALL },fetch = FetchType.EAGER)
    @JoinTable(name = "post_tags", joinColumns = {
        @JoinColumn(name = "post_id", referencedColumnName = "post_id")
    }, inverseJoinColumns = {
        @JoinColumn(name = "tag_id", referencedColumnName = "tag_id")
    })

@JsonManagedReference
    private Set<Tags> tags = new HashSet<Tags>();
}

package com.example.demo.hibernetexample.posttag.entity;

import jakarta.persistence.*;
import lombok.*;

import java.util.HashSet;
import java.util.Set;

@Entity
@Table(name = "tags")
@AllArgsConstructor
@NoArgsConstructor
@Getter
@Setter
@Builder
@ToString
public class Tags {
    @Id
    @GeneratedValue(strategy = jakarta.persistence.GenerationType.IDENTITY)
    @Column(name = "tag_id")
    private Integer tagId;
    @Column(name = "tag_name")
    private String tagName;
    @ManyToMany(mappedBy = "tags", cascade = { CascadeType.ALL },fetch = FetchType.EAGER)
    

@JsonBackReferenceprivate

 Set<Post> posts = new HashSet<Post>();
}

springbot interview question

 

https://news.lunartech.ai/cracking-java-interview-bcc73fb75be9