Time out when i access Azure Data Lake Gen2 in Azure Function with ADLS java sdk V12

My function code as below:

package org.example;

import com.azure.core.http.rest.PagedIterable;
import com.azure.storage.common.StorageSharedKeyCredential;
import com.azure.storage.file.datalake.DataLakeFileSystemClient;
import com.azure.storage.file.datalake.DataLakeServiceClient;
import com.azure.storage.file.datalake.DataLakeServiceClientBuilder;
import com.azure.storage.file.datalake.models.ListPathsOptions;
import com.azure.storage.file.datalake.models.PathItem;
import com.microsoft.azure.functions.*;
import com.microsoft.azure.functions.annotation.AuthorizationLevel;
import com.microsoft.azure.functions.annotation.FunctionName;
import com.microsoft.azure.functions.annotation.HttpTrigger;

import java.util.Iterator;
import java.util.Optional;

/**
 * Azure Functions with HTTP Trigger.
 */
public class Function {

    public static String accountName = "***";
    public static String accountKey = "***";

    @FunctionName("HttpExample")
    public HttpResponseMessage run(
            @HttpTrigger(name = "req", methods = {HttpMethod.GET, HttpMethod.POST}, authLevel = AuthorizationLevel.ANONYMOUS) HttpRequestMessage<Optional<String>> request,
            final ExecutionContext context) {
        context.getLogger().info("Java HTTP trigger processed a request.+++++");

        DataLakeServiceClient dataLakeServiceClient = GetDataLakeServiceClient(accountName, accountKey);
        DataLakeFileSystemClient dataLakeFileSystemClient = GetFileSystem(dataLakeServiceClient);

        String name = ListFilesInDirectory(dataLakeFileSystemClient, context);

        if (name == null) {
            return request.createResponseBuilder(HttpStatus.BAD_REQUEST).body("Please pass a name on the query string or in the request body").build();
        } else {
            return request.createResponseBuilder(HttpStatus.OK).body("List File Names:, " + name).build();
        }
    }

    static public DataLakeServiceClient GetDataLakeServiceClient
            (String accountName, String accountKey) {

        StorageSharedKeyCredential sharedKeyCredential =
                new StorageSharedKeyCredential(accountName, accountKey);

        DataLakeServiceClientBuilder builder = new DataLakeServiceClientBuilder();

        builder.credential(sharedKeyCredential);
        builder.endpoint("https://" + accountName + ".dfs.core.windows.net");

        return builder.buildClient();
    }

    static public DataLakeFileSystemClient GetFileSystem
            (DataLakeServiceClient serviceClient) {

        return serviceClient.getFileSystemClient("test");
    }

    static public String ListFilesInDirectory(DataLakeFileSystemClient fileSystemClient, ExecutionContext context) {

        ListPathsOptions options = new ListPathsOptions();
        options.setPath("");
        fileSystemClient.listPaths().forEach( path -> context.getLogger().info(path.getName()));

        return "ABC";
    }
}

The java sdk link: https://azuresdkdocs.blob.core.windows.net/$web/java/azure-storage-file-datalake/12.0.0-preview.6/index.html

Based on my own troubleshooting, the code always hangs on the line :
fileSystemClient.listPaths().forEach( path -> context.getLogger().info(path.getName()));

No any responses here. I tested above code outside Azure function, let's say the Main method,everything works. So i think the code is fine. Anyone met the same issue as same as me. Is there any restrictions in the Azure Function to access ADLS gen2 with java sdk? Please help.