It's required to have a JDK installed to build.
Make sure the JAVA_HOME environment variable is set.
To build the driver, run make release.
This will produce two jars in the build folder:
build/release/duckdb_jdbc.jar
build/release/duckdb_jdbc_tests.jar
The tests can be ran using using make test or this command
java -cp "build/release/duckdb_jdbc_tests.jar:build/release/duckdb_jdbc.jar" org/duckdb/TestDuckDBJDBC
This optionally takes an argument to only run a single test, for example:
java -cp "build/release/duckdb_jdbc_tests.jar:build/release/duckdb_jdbc.jar" org/duckdb/TestDuckDBJDBC test_valid_but_local_config_throws_exception