Spring Boot Hazelcast Cache Example

By | 2018-11-11T09:56:16+00:00 October 15th, 2018|Spring Boot|0 Comments

Hazelcast is an in-memory distributed caching mechanism. In this tutorial, I am going to show you how to enable the Spring Boot Hazelcast cache.

Spring Boot Hazelcast Cache:

Hazelcast is an in-memory caching mechanism provided by the spring boot. Spring boot auto-configures the Hazelcast instance if the hazelcast is available in our application’s classpath and the required configuration is available.

Spring Boot Hazelcast Example:

Here I am going to create a simple spring boot rest service to read Items from the database using the hazelcast cache.


  • Spring Boot 2.0.5 RELEASE
  • Hazelcast
  • Spring Boot JDBC
  • MySQL
  • Java 8

Project Structure:

Spring Boot Hazelcast Cache Example

Hazelcast Dependency:

Add the below hazelcast dependencies in pom.xml

hazelcast dependencies

Complete pom.xml

<?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">

  <description>Spring Boot Hazelcast Cache Example</description>

    <relativePath/> <!-- lookup parent from repository -->


Database configuration details.

spring.datasource.driver-class-name: com.mysql.jdbc.Driver
spring.datasource.url: jdbc:mysql://localhost:3306/otp
spring.datasource.username: root
spring.datasource.password: Chandu@123

Hazelcast configuration.

Creating a Hazelcast Config bean with the required configuration.

package com.onlinetutorialspoint.config;

import com.hazelcast.config.Config;
import com.hazelcast.config.EvictionPolicy;
import com.hazelcast.config.MapConfig;
import com.hazelcast.config.MaxSizeConfig;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

public class HazelcastCacheConfig {

    public Config hazelcastConfig(){
       return new Config().setInstanceName("hazelcast-instance")
                .addMapConfig(new MapConfig().setName("itemCache")
                .setMaxSizeConfig(new MaxSizeConfig(300,MaxSizeConfig.MaxSizePolicy.FREE_HEAP_SIZE))


Mapping the itemCache to hazelCache config and giving eviction policy as LRU (Last Recently Used).

Preparing ItemCache component.

package com.onlinetutorialspoint.cache;

import com.onlinetutorialspoint.model.Item;
import com.onlinetutorialspoint.repo.ItemRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.CachePut;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Component;

public class ItemCache {

    ItemRepository itemRepo;

    @Cacheable(value="itemCache", key="#id")
    public Item getItem(int id){
        System.out.println("In ItemCache Component..");
        Item item = null;
            item = itemRepo.getItem(id);
        }catch(Exception e){
        return item;

    @CacheEvict(value="itemCache",key = "#id")
    public int deleteItem(int id){
        System.out.println("In ItemCache Component..");
        return itemRepo.deleteItem(id);

    public void updateItem(Item item){
        System.out.println("In ItemCache Component..");

@Cachable: Is used to adding the cache behavior to a method. We can also give the name to it, where the cache results would be saved.
@CacheEvict: Is used to remove the one or more cached values. allEntries=true parameter allows us to remove all entries from the cache.
@CachePut: Is used to update the cached value.

Creating an Item model

package com.onlinetutorialspoint.model;

import java.io.Serializable;

public class Item implements Serializable {
    private int id;
    private String name;
    private String category;

    public Item() {

    public Item(int id, String name, String category) {
        this.id = id;
        this.name = name;
        this.category = category;

    public int getId() {
        return id;

    public void setId(int id) {
        this.id = id;

    public String getName() {
        return name;

    public void setName(String name) {
        this.name = name;

    public String getCategory() {
        return category;

    public void setCategory(String category) {
        this.category = category;

Creating Item Repository responsible to read items from MySQL database using JdbcTemplate.

package com.onlinetutorialspoint.repo;

import com.onlinetutorialspoint.model.Item;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;

public class ItemRepository {

    JdbcTemplate template;

    /*Getting a specific item by item id from table*/
    public Item getItem(int itemId){
        System.out.println("Reading Item From Repository..");
        String query = "SELECT * FROM ITEM WHERE ID=?";
        return template.queryForObject(query,new Object[]{itemId},new BeanPropertyRowMapper<>(Item.class));

    /*delete an item from database*/
    public int deleteItem(int id){
        String query = "DELETE FROM ITEM WHERE ID =?";
        int size = template.update(query,id);
        return size;

    /*update an item from database*/
    public void updateItem(Item item){
        String query = "UPDATE ITEM SET name=?, category=? WHERE id =?";
                new Object[] {
                        item.getName(),item.getCategory(), Integer.valueOf(item.getId())


Creating rest endpoints to access item data

package com.onlinetutorialspoint.controller;

import com.onlinetutorialspoint.cache.ItemCache;
import com.onlinetutorialspoint.model.Item;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

public class ItemController {

    ItemCache itemCache;
    public ResponseEntity<Item> getItem(@PathVariable int itemId){
        long start = System.currentTimeMillis();
        Item item = itemCache.getItem(itemId);
        long end = System.currentTimeMillis();
        System.out.println("Took : " + ((end - start) / 1000+" sec."));
        return new ResponseEntity<Item>(item, HttpStatus.OK);

    public ResponseEntity<Item> updateItem(@RequestBody Item item){
        if(item != null){
        return new ResponseEntity<Item>(item, HttpStatus.OK);

    public ResponseEntity<Void> deleteItem(@PathVariable int id){
        return new ResponseEntity<Void>(HttpStatus.ACCEPTED);


Main class with the @EnablingCache annotation to enable the cache.

package com.onlinetutorialspoint;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.EnableCaching;

public class SpringBootHazelcastCacheExampleApplication {

  public static void main(String[] args) {
    SpringApplication.run(SpringBootHazelcastCacheExampleApplication.class, args);

Run the application:

mvn spring-boot: run
mvn spring-boot:run

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 :: Spring Boot ::        (v2.0.5.RELEASE)

2018-10-14 17:43:02.414  INFO 5196 --- [           main] ringBootHazelcastCacheExampleApplication : Starting SpringBootHazelcastCacheExampleApplication on DESKTOP-RN4SMHT with PID 5196 (E:\work\SpringBoot_Hazelcast_Cache_Example\target\classes started by Lenovo in E:\work\SpringBoot_Hazelcast_Cache_Example)
2018-10-14 17:43:02.414  INFO 5196 --- [           main] ringBootHazelcastCacheExampleApplication : No active profile set, falling back to default profiles: default

Access the application

Spring Boot Hazelcast Cache Example output

Console logs:

In ItemCache Component..
Reading Item From Repository..
Took : 3 sec.

For the first time when we access the item 1, it took 3 Sec to get the data from the database.

Accessing the same item again and observe the log statements.

Spring Boot Hazelcast Cache Example output
Took : 0 sec.

For the second time, it took zero seconds to get the same data because for this time the data came from the hazelCast cache.

Happy Learning 🙂

Download Example

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