[BUG] supportJava6=true creates a client with dependencies that do not support Java 6

[GiamBoscaro]

Goodmorning,

I am trying to generate an API client in Java with Open API. Sadly, it needs to work with java 6. I enable the flag, and everything works fine in the development environment (Eclipse) running on Java 11 with compliance for Java 6. When I export the JAR and try to run it in the staging environment with JRE 1.6, I get the error ClassDefNotFound okhttp3/Interceptor. If I try to download this dependency from Maven I then get Unsupported major.minor version 52.0.

So, I am wondering if the flag supportJava6 actually does something or not, since it seems like it requires at least Java 8.

Am I doing something wrong?

I generated the client from the CLI Docker like this:

// from docker-compose.yml

version: "3.6"
services:

  openapi:
    image: openapitools/openapi-generator-cli
    volumes:
      - ".:local"
    command: generate -g java -I local/in/api.yml -o /local/out/java-client --additional-properties=supportJava6=true

Best regards

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[wing328]

I think only the jersey2 library supports Java 6. Can you please give it a try?

[GiamBoscaro]

I can try again, but from what I remembered I still got errors, like:

• Compiling error: getOrDefault is used but requires java 8. No problem, fixed with an if statement.
• Then at runtime I get Jackson/databind/ISO8601DateFormat: Unsupported major.minor version 51.0

[wing328]

	supportJava6
	    Whether to support Java6 with the Jersey1 library. This option has been deprecated and will be removed in the 5.x release (Default: false)

My bad. Looks like only jersey1 supports Java6.

[wing328]

As communicated before, we'll remove the supportJava6 option in 5.x

I've filed #8514

[GiamBoscaro]

From what I remember, even with jersey1 I had problems at runtime with some unsupportedd major minor version 51.0 errors. Some libraries used by openapi still need java7 even with jersey1 and supportJava6=true