private void init() {
    cache = (InternalCache) CacheFactory.getAnyInstance();
    if (cache == null) {
      throw new RuntimeException("Cache could not be found in JCAManagedConnection");
    }
    LogWriter logger = cache.getLogger();
    if (logger.fineEnabled()) {
      logger.fine("JCAManagedConnection:init. Inside init");
    }
    transactionManager = cache.getTxManager();
    initialized = true;
  }
Invalidate and remove the {@link GFConnectionImpl} from the connections collection.
The approach to use removeAll instead of Iterator.remove is purely a performance optimization
to avoid creating all the intermediary collections that will be created when using the single
remove operation.
geode-core/src/jca/java/org/apache/geode/internal/ra/spi/JCAManagedConnection.java