[JAVA] Implement #10176 (for 3.x)

[michaelkourlas]

Implemented #10176 (from the swagger-codegen repo) for jersey1, jersey2, resttemplate, and okhttp-gson. Each API call now has up to two additional methods:

• one containing only required parameters
• one containing required parameters + optional parameters, the latter in a builder-style format

It was necessary to fix a bug where the body parameter did not appear in the requiredParams list.

[michaelkourlas]

@HugoMario @frantuma

[jayMcoder]

@michaelkourlas - Solution looks neat. One of the API that I consume has 10 optional parameters and I had to set null for all of them. Can this be added to the resttemplate type as well?

[michaelkourlas]

I'd like the maintainers to confirm whether they're interested in merging this PR before I make any further additions.

[HugoMario]

hey @michaelkourlas thanks for this PR, let me know once is ready to review it and merge it

[michaelkourlas]

@HugoMario I've added support for this pattern for resttemplate as requested, so I believe this PR (as well as this one and this one) are ready to be reviewed.

[michaelkourlas]

@HugoMario Just notifying you that this PR (as well as this one and this one) are ready to be reviewed.