We are using Lettuce java client to connect to AWS Elasticache (Valkey engine, Serverless, version 8.0) from Java springboot application (JDK 17 & springboot version 3.2.5)

Below is the method where I am trying to read multiple keys from elasticache using jsonMGet().

public List<JsonValue> readMultipleKeys(List<String> keys) {

        RedisAsyncCommands<String, String> async = null;
        try {
            async = redisCacheClient.connect().async();
            return async.jsonMGet(JsonPath.ROOT_PATH, keys.toArray(new String[0])).get();
        } catch (Exception e) {
            log.error("Exception while reading multiple keys from Cache: " + e.getMessage());
            return null;
        }
    }

Everything works perfectly fine as long as all the keys from the input list are present in Cache. But if any key (lets say 1 out of 100 input keys) doesn't exist in cache, it is throwing below error and not returning any other values.

Exception while reading from Cache: java.lang.NullPointerException: Cannot invoke "java.nio.ByteBuffer.remaining()" because "bytes" is null

I want the method to return all the keys that are PRESENT in cache and ignore the keys that doesn't exist.

We are using Lettuce java client to connect to AWS Elasticache (Valkey engine, Serverless, version 8.0) from Java springboot application (JDK 17 & springboot version 3.2.5)

Below is the method where I am trying to read multiple keys from elasticache using jsonMGet().

public List<JsonValue> readMultipleKeys(List<String> keys) {

        RedisAsyncCommands<String, String> async = null;
        try {
            async = redisCacheClient.connect().async();
            return async.jsonMGet(JsonPath.ROOT_PATH, keys.toArray(new String[0])).get();
        } catch (Exception e) {
            log.error("Exception while reading multiple keys from Cache: " + e.getMessage());
            return null;
        }
    }

Everything works perfectly fine as long as all the keys from the input list are present in Cache. But if any key (lets say 1 out of 100 input keys) doesn't exist in cache, it is throwing below error and not returning any other values.

Exception while reading from Cache: java.lang.NullPointerException: Cannot invoke "java.nio.ByteBuffer.remaining()" because "bytes" is null

I want the method to return all the keys that are PRESENT in cache and ignore the keys that doesn't exist.

• java
• json
• spring-boot
• amazon-elasticache
• lettuce

• Which version of the Lettuce driver are you using? A similar issue was addressed with this issue in the 6.5.5 release, see github/redis/lettuce/issues/3196 – Tihomir Mateev Commented 7 hours ago

2 Answers 2

EDIT: This seems to be addressed in Lettuce 6.5.5 and later

A NullPointerException is almost certainly a bug.

I've taken the liberty to create one in the GitHub tracker for you: https://github/redis/lettuce/issues/3241

I suggest we continue the conversation there.

Have you tried using other client libraries? Valkey-Glide Java supports JSON. See:
https://github/valkey-io/valkey-glide/tree/main/java
https://github/valkey-io/valkey-glide/wiki/General-Concepts#modules-api

Disclaimer: I'm a Valkey-Glide maintainer and would be happy to help if you open an issue!