JAVA EE: Java Tutorial : Java IO (PrintStream-out-err)

Monday 22 August 2016

Java Tutorial : Java IO (PrintStream-out-err)

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https://www.youtube.com/watch?v=mZ7NEvJm4pU&list=UUhwKlOVR041tngjerWxVccw

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Java Tutorial : Java IO (PrintStream-out-err)

PrintStreamDemo1.java

import java.io.IOException;
import java.io.PrintStream;

public class PrintStreamDemo1
{

    public static void main(String[] args) throws IOException

    {
        PrintStream printStream = null;
        try
        {
            /*
             * System.out
             * ----------
             * The "standard" output stream. This stream is
             * already open and ready to accept output data.
             * Typically this stream corresponds to display
             * output or another output destination
             * specified by the host environment or user.
             */
            printStream = new PrintStream(System.out);
            printStream.println(2500);
            printStream.println("Hello Peter");
            printStream.println(25.988);
            printStream.println(true);
        }
        finally
        {
            if (printStream != null)
            {
                printStream.close();
            }
        }

    }
}

Output

2500
Hello Peter
25.988
true

PrintStreamDemo2.java

import java.io.IOException;
import java.io.PrintStream;

public class PrintStreamDemo2
{

    public static void main(String[] args) throws IOException

    {
        PrintStream printStream = null;
        try
        {
            /*
             * System.err
             * ---------
             * The "standard" error output stream. This
             * stream is already open and ready to accept
             * output data. Typically this stream
             * corresponds to display output or another
             * output destination specified by the host
             * environment or user. By convention, this
             * output stream is used to display error
             * messages or other information that should
             * come to the immediate attention of a user
             * even if the principal output stream, the
             * value of the variable out, has been
             * redirected to a file or other destination
             * that is typically not continuously monitored.
             */
            printStream = new PrintStream(System.err);
            printStream.println("Error occured.");          
        }
        finally
        {
            if (printStream != null)
            {
                printStream.close();
            }
        }

    }
}

Output

Error occured.

PrintStreamDemo3.java

import java.io.IOException;

public class PrintStreamDemo3
{

    public static void main(String[] args) throws IOException

    {
        System.out.printf("%f", 25.89);
        System.err.println("\nSome error occured");
    }
}