Sending string to java process

[moiit]

From Qt application, starts a java subprocess, and sends a string to it. No need any response from java process.
I want to use QProcess because i think it is more simple than QTcpSocket(not sure).
However, it seems the java subprocess cant recieve the string.
Consider the codes writed below:

Qt Code:

QProcess *java= new QProcess();
java->setWorkingDirectory("F:/");
java->start("java Test");
if(!java->waitForStarted())
    return false;
java->closeWriteChannel();
QString str = "Test String";
//qDebug() << qPrintable(str);
std::cout<<qPrintable(str)<<std::endl;
//QTextStream out(stdout);
//out<<str;

QProcess *java= new QProcess();
java->setWorkingDirectory("F:/");
java->start("java Test");
if(!java->waitForStarted())
    return false;
java->closeWriteChannel();
QString str = "Test String";
//qDebug() << qPrintable(str);
std::cout<<qPrintable(str)<<std::endl;
//QTextStream out(stdout);
//out<<str;

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Java Code:

BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
String str;
try {
        str = reader.readLine(); }
catch (IOException exc) {
         System.out.println("Can't read from stdin!");
         return ; }
if(str != null)
    System.out.println(str);

BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
String str;
try {
        str = reader.readLine(); }
catch (IOException exc) {
         System.out.println("Can't read from stdin!");
         return ; }
if(str != null)
    System.out.println(str);

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How can i get it work as expected? Any advice will be thankful!