Improve: Java APIを色々改善 #2247

Job	Run time
actionlint	18s
rust-unit-test	4m 27s
rust-lint	3m 38s
shellcheck	16s
validate-cargo-lock	26s
build-and-test-java-api (windows-latest)	8m 2s
build-and-test-python-api (windows-latest)	5m 33s
build-and-test-java-api (macos-latest)	4m 5s
build-and-test-python-api (macos-latest)	5m 28s
build-and-test-java-api (ubuntu-latest)	2m 34s
build-and-test-python-api (ubuntu-latest)	3m 48s
build-unix-cpp-example (macos-latest, osx-x64-cpu-cpp-shared)	2m 30s
build-windows-cpp-example	6m 17s
build-unix-cpp-example (ubuntu-latest, linux-x64-cpu-cpp-shared)	2m 31s
c-header	1m 13s
rust-integration-test-strategy-matrix	1s
rust-integration-test (windows-2019, directml)	6m 6s
rust-integration-test (macos-11)	2m 26s
rust-integration-test (ubuntu-20.04)	1m 55s
	1h 1m 34s

Provide feedback