in src/main/java/org/apache/skywalking/banyandb/v1/client/BanyanDBClient.java [162:171]
public BanyanDBClient(String[] targets, Options options) {
String[] tt = Preconditions.checkNotNull(targets, "targets");
checkState(tt.length > 0, "targets' size must be more than 1");
tt = Arrays.stream(tt).filter(t -> !Strings.isNullOrEmpty(t)).toArray(size -> new String[size]);
checkState(tt.length > 0, "valid targets' size must be more than 1");
this.targets = tt;
this.options = options;
this.connectionEstablishLock = new ReentrantLock();
this.metadataCache = new MetadataCache(this);
}