The general answer to this is yes. If that were not true, connection pools, for example, would not be possible. As always, however, this is completely dependent on the JDBC driver.

You can find out the theoretical maximum number of active Connections that your driver can obtain via the DatabaseMetaData.getMaxConnections method. Although there is some ambiguity in the API documentation, the JDBC API Tutorial and Reference, 2nd Ed: Java 2 clarifies with "that can be made through this driver instance."