in alloydb-jdbc-connector/src/main/java/com/google/cloud/alloydb/ConnectionConfig.java [114:121]
private static void validateProperties(Properties props) {
final String instanceNameStr = props.getProperty(ALLOYDB_INSTANCE_NAME, "");
Preconditions.checkArgument(
InstanceName.isParsableFrom(instanceNameStr),
String.format(
"'%s' must have format: projects/<PROJECT>/locations/<REGION>/clusters/<CLUSTER>/instances/<INSTANCE>",
ALLOYDB_INSTANCE_NAME));
}