Analyzing heap dump from OutOfMemoryError in Java

Question

my Java program is constantly getting OutOfMemoryError, and I believe there is a memory leak somewhere. While researching this issue, multiple sites suggested the Eclipse Memory Analyzer tool, so I added the -XX:+HeapDumpOnOutOfMemoryError flag to the command, to get the heap dump the next time the error occurs. Upon checking the dump, the objects taking up the most space were "17,481 instances of "com.couchbase.client.core.deps.org.LatencyUtils.LatencyStats", loaded by "org.springframework.boot.loader.LaunchedURLClassLoader @ 0x6c7c24510" occupy 1,978,652,856 (59.03%) bytes."

I thought this was the logger printing out too many logs, since the Java Couchbase code prints a LOT of logs on the INFO level, so I tried setting the log level to WARN but after trying it out, same result. Would appreciate any insight or suggestions, thank you.

---

EDIT: some parts of our code that calls Couchbase:

@Autowired
private CouchbaseConfig couchbaseConfig;

public List<ArLedger> getBranchArLedgers(String branchId, String fromDate, String toDate) {
        
    String query = Queries.GET_AR_LEDGER_BY_BRANCH_AND_DATE_RANGE;
    query = MessageFormat.format(query, branchId, fromDate, toDate);

    Cluster cluster = null;
        
    try {
        cluster = couchbaseConfig.connectToCouchbase();
        QueryResult queryResult = cluster.query(query);
    
        return queryResult.rowsAs(ArLedger.class);
    } catch (Exception e) {
        e.printStackTrace();
        return Collections.emptyList();
    } finally {
        if (cluster != null) {
            cluster.disconnect();
        }
    }
}

And the connectToCouchbase() from the injected CouchbaseConfig:

@Value("${app.couchbase.connection-string}")
private String connectionString;

@Value("${app.couchbase.username}")
private String username;

@Value("${app.couchbase.password}")
private String password;

public Cluster connectToCouchbase() {
    return Cluster.connect(connectionString, username, password);
}

---

EDIT 2: Updated the code to follow dnault's suggestion, and a screenshot of the error that occurs when running the code:

CouchbaseConfig:

@Configuration
public class CouchbaseConfig extends AbstractCouchbaseConfiguration {

    @Autowired
    private ApplicationContext context;

    @Value("${app.couchbase.connection-string}")
    private String connectionString;

    @Value("${app.couchbase.username}")
    private String username;

    @Value("${app.couchbase.password}")
    private String password;

    @Bean
    public Cluster couchbaseCluster() {
        return Cluster.connect(connectionString, username, password);
    }
}

The repository code:

@Repository
public class ArLedgerRepository {
    
    @Autowired
    private Cluster couchbaseCluster;

    public List<ArLedger> getAllBranchArLedgers(String branchId, String fromDate, String toDate) {
        
        String query = Queries.GET_ALL_AR_LEDGERS_BY_BRANCH_AND_DATE_RANGE;
        query = MessageFormat.format(query, branchId, fromDate, toDate);
        try {
            
            QueryResult queryResult = couchbaseCluster.query(query);
    
            return queryResult.rowsAs(ArLedger.class);
        } catch (Exception e) {
            e.printStackTrace();
            return Collections.emptyList();
        } finally {
            couchbaseCluster.disconnect();
        }
    }
}

And the screenshot of the error that occurs when the repository method is called:

Answer 1

@kei101895

There is already a couchbaseCluster bean defined in AbstractCouchbaseConfiguration. If I'm not mistaken, that is the Cluster that @Autowired will use (I believe because it was needed previously by other @Beans and already created).

That couchbaseCluster uses the couchbaseClusterEnvironment bean which has a destroyMethod specified. This will ensure that shutdown() is called on the ClusterEnvironment

@Bean(destroyMethod = "shutdown")
public ClusterEnvironment couchbaseClusterEnvironment() {...

To customize the environment for the provided Cluster @Bean, one can @Override the configureEnvironment(builder) method in the couchbase config class.

If you really want/need to have your own Cluster bean, you can give it a name in @Bean("myBeanName") and then reference it with:

ApplicationContext ac = new AnnotationConfigApplicationContext(Config.class); myCluster = (Cluster) ac.getBean("myBeanName");