[3.0.0] Update all 'java' examples

[jmini]

As discussed in: swagger-api/swagger-codegen-generators#52 generate all possible -l java examples with current 1.0.0-SNAPSHOT version of swagger-codegen-generators.

Folder samples/client/petstore/java/ is updated.

Examples should compile.

[jmini]

@HugoMario: CI is OK. Can you merge this? Then we will be able to adress the different problems and activate the scripts that are commented.

[HugoMario]

thanks @jmini

[jmini]

In this PR following scripts were run to update the samples:

#!/bin/sh
# update # java clients, see https://github.com/swagger-api/swagger-codegen-generators/issues/52

./bin/java-petstore-feign.sh
./bin/java-petstore-jersey1.sh
./bin/java-petstore-jersey2.sh
./bin/java-petstore-resteasy.sh
./bin/java-petstore-resttemplate-withxml.sh
./bin/java-petstore-resttemplate.sh
./bin/java-petstore-retrofit.sh
./bin/java-petstore-retrofit2-play24.sh
./bin/java-petstore-retrofit2-play25.sh
./bin/java-petstore-retrofit2.sh
./bin/java-petstore-retrofit2rx.sh
./bin/java-petstore-retrofit2rx2.sh
./bin/java-petstore-vertx.sh
./bin/java8-petstore-jersey2.sh

There is more to come, when the findings in swagger-api/swagger-codegen-generators#52 are addressed.