Simplify afterPropertiesSet() Method in `RedisTemplate` Using Objects.requireNonNullElse

The afterPropertiesSet() method currently contains multiple null checks and assignments that can be simplified. By utilizing Java 9’s Objects.requireNonNullElse and Objects.requireNonNullElseGet methods, we can make the code more concise, readable, and maintainable.

AS-IS

public void afterPropertiesSet() {
    super.afterPropertiesSet();

    if (defaultSerializer == null) {
        defaultSerializer = new JdkSerializationRedisSerializer(
            classLoader != null ? classLoader : this.getClass().getClassLoader());
    }

    if (enableDefaultSerializer) {
        if (keySerializer == null) {
            keySerializer = defaultSerializer;
        }
        if (valueSerializer == null) {
            valueSerializer = defaultSerializer;
        }
        if (hashKeySerializer == null) {
            hashKeySerializer = defaultSerializer;
        }
        if (hashValueSerializer == null) {
            hashValueSerializer = defaultSerializer;
        }
    }

    if (scriptExecutor == null) {
        this.scriptExecutor = new DefaultScriptExecutor<>(this);
    }

    initialized = true;
}

TO-BE

public void afterPropertiesSet() {
    super.afterPropertiesSet();

    defaultSerializer = Objects.requireNonNullElseGet(
        defaultSerializer,
        () -> new JdkSerializationRedisSerializer(
            Objects.requireNonNullElse(classLoader, getClass().getClassLoader()))
    );

    if (enableDefaultSerializer) {
        keySerializer = Objects.requireNonNullElse(keySerializer, defaultSerializer);
        valueSerializer = Objects.requireNonNullElse(valueSerializer, defaultSerializer);
        hashKeySerializer = Objects.requireNonNullElse(hashKeySerializer, defaultSerializer);
        hashValueSerializer = Objects.requireNonNullElse(hashValueSerializer, defaultSerializer);
    }

    scriptExecutor = Objects.requireNonNullElseGet(
        scriptExecutor,
        () -> new DefaultScriptExecutor<>(this)
    );

    initialized = true;
}
}

Start at RedisTemplate.afterPropertiesSet() and compare its current null-handling branches with the proposed Objects-based form. Check the surrounding imports and relevant existing tests, then verify that initialization and serializer defaults remain unchanged while the method becomes more concise.