forked from loafle/openapi-generator-original
* Partially revert "replace deprecated ISO8601Utils with StdDateFormat (#17052)" This partially reverts commit 76560e34c9aacd9d7593ac45bd204e2edf38abd9, namely anything related to generators and samples using GSON instead of Jackson. Changes to Jackson-only generation and generator-online regarding RFC3339DateFormat are not being reverted. * Test for default serialization library fallback * Convert repetitive tests to parameterized test * Add regression test for #18515 * [FEIGN] Only include <jackson-databind-version> property in pom.xml when required * [RETROFIT2] Only include jackson-databind in gradle file when actually required * [FEIGN] Don't include jackson dep's in sbt file when GSON is selected * [FEIGN] Don't include jackson dep's in gradle file when GSON is selected * DRY refactor JavaClientCodegen test code, increase readability - use fluent assertions - use helper method newTempFolder() - use Java 9 static factory methods for maps - don't declare variables that are only used once - group declarations and usages - use non-blocking java.nio.file API wherever possible * Regenerate samples