Writes to stdin not recevied directly #1768

Hi, I'm a little stuck right now. I'm runing a java application inside a docker container and I want to send a command to it. I'm using the following code to attach to the container:

this.stdOut = new PipedOutputStream();
this.stdIn = new PipedInputStream(this.stdOut);

this.dockerClient.attachContainerCmd(this.containerId)
        .withLogs(true)
        .withStdOut(true)
        .withStdErr(true)
        .withStdIn(this.stdIn)
        .withTimestamps(false)
        .withFollowStream(true)
        .exec(new ServiceLogCacheAdapter());

Everything works fine and I can receive data written to stdout/stderr. But when I try to send data to the stdout stream the data is not received by the application until the application sends out a message to std out/err. I'm currently not sure if this is an issue on my end and I'm hoping someone can help me with this. Thanks in advance!