private String makeKey(String uri, String user, char[] password) {
        requireNonNull(uri);
        // user nullable
        // password nullable
        return uri + user + ((password == null) ? "null" : new String(password));
    }
A fully concurrent implementation of a connection pool.

@author Per Minborg
runtime-parent/runtime-core/src/main/java/com/speedment/runtime/core/internal/component/ConnectionPoolComponentImpl.java