#vulnerable code 
                                @Override
    public boolean connect(final Endpoint endpoint) {
        if (this.rpcClient == null) {
            throw new IllegalStateException("Client service is not inited.");
        }
        if (isConnected(endpoint)) {
            return true;
        }
        try {
            final PingRequest req = PingRequest.newBuilder() //
                .setSendTimestamp(System.currentTimeMillis()) //
                .build();
            final ErrorResponse resp = (ErrorResponse) this.rpcClient.invokeSync(endpoint.toString(), req,
                this.defaultInvokeCtx, this.rpcOptions.getRpcConnectTimeoutMs());
            return resp.getErrorCode() == 0;
        } catch (final InterruptedException e) {
            Thread.currentThread().interrupt();
            return false;
        } catch (final RemotingException e) {
            LOG.error("Fail to connect {}, remoting exception: {}.", endpoint, e.getMessage());
            return false;
        }
    } 
                            #location 3 
                            #vulnerability type THREAD_SAFETY_VIOLATION
#fixed code
                                @Override
    public boolean connect(final Endpoint endpoint) {
        final RpcClient rc = this.rpcClient;
        if (rc == null) {
            throw new IllegalStateException("Client service is uninitialized.");
        }
        if (isConnected(rc, endpoint)) {
            return true;
        }
        try {
            final PingRequest req = PingRequest.newBuilder() //
                .setSendTimestamp(System.currentTimeMillis()) //
                .build();
            final ErrorResponse resp = (ErrorResponse) rc.invokeSync(endpoint.toString(), req, this.defaultInvokeCtx,
                this.rpcOptions.getRpcConnectTimeoutMs());
            return resp.getErrorCode() == 0;
        } catch (final InterruptedException e) {
            Thread.currentThread().interrupt();
            return false;
        } catch (final RemotingException e) {
            LOG.error("Fail to connect {}, remoting exception: {}.", endpoint, e.getMessage());
            return false;
        }
    }