I want to migrate me services to use Feature Flag Capabilities from: LaunchDarkly to AWS AppConfig feature flags
Are they work the same?
What are the major differences?
Can I use Java Client?
There is overlap between the two solutions. However, there are some key differences, which may or may not matter to you, depending on your use-case.
For example, AWS AppConfig has native integrations with other AWS services like Lambda; see this video: https://www.youtube.com/watch?v=sq2HcRMLaLU. Pricing is different too (AWS AppConfig is pay-as-you-go). And per your question, AWS AppConfig does have AWS Java SDK support: https://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/com/amazonaws/services/appconfig/AmazonAppConfigClient.html
FYI - I work on AWS AppConfig.