Procuing Output to a text file is showing peculier behaviour

[naveen shrimal]

HI to al,
I am facing problem while wrapping the FileInputStream into BufferedInputStream. I am not getting the desired putput on b.txt though the console shows the whole text of a.txt.
When I look arounf I finad two ways out:-
1. either i add a line that will forcefully flush the contents of BufferedInputStream
2. I should not close the FileUotputStream in finally clause.

I did not understand the second way....Why so happening? Because Finally executes in last.

one more question is that should I close both FileInputStream oblect and its Wrapper BufferedInputStream object or just the BufferedInputStream object's closing is enough.

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

public class CopyViaBuffer {
	public static void main(String[] args) throws IOException {
		int c;
		FileInputStream fileInputStream=null;
		BufferedInputStream bufferedInputStream=null;
		FileOutputStream fileOutputStream=null;
		BufferedOutputStream bufferedOutputStream=null;
		try{
	     fileInputStream=new FileInputStream("a.txt");
		bufferedInputStream=new BufferedInputStream(fileInputStream);
		fileOutputStream=new FileOutputStream("b.txt");
		 bufferedOutputStream=new BufferedOutputStream(fileOutputStream);
		 while((c=bufferedInputStream.read())!=-1){
			 System.out.print((char)c);
			 bufferedOutputStream.write(c);
		 }
		 
		//bufferedOutputStream.flush();
		}
		finally{
			fileInputStream.close();
			bufferedInputStream.close();
			//fileOutputStream.close();
			bufferedOutputStream.close();
		}
		
	}

}

[Jesper de Jong]

If you look at the API documentation of class BufferedOutputStream, you'll see that it inherits its close() method from FilteredOutputStream. And the documentation of the close() method for FilteredOutputStream says:

Closes this output stream and releases any system resources associated with the stream.

The close method of FilterOutputStream calls its flush method, and then calls the close method of its underlying output stream.

So you do not need to flush the stream explicitly or call close on on the underlying FileOutputStream.

You get a problem because you close the FileOutputStream in line 29, before your close the BufferedOutputStream in line 30. If you close the FileOutputStream first, then BufferedOutputStream can't flush the data anymore that it still might have in its buffer. So, the solution is to not close the FileOutputStream yourself; just let the BufferedOutputStream do that.

Make the finally-block look like this:

finally {
    bufferedInputStream.close();
    bufferedOutputStream.close();
}

[naveen shrimal]

Jesper de Jong wrote:If you look at the API documentation of class BufferedOutputStream, you'll see that it inherits its close() method from FilteredOutputStream. And the documentation of the close() method for FilteredOutputStream says:

Closes this output stream and releases any system resources associated with the stream.

The close method of FilterOutputStream calls its flush method, and then calls the close method of its underlying output stream.

So you do not need to flush the stream explicitly or call close on on the underlying FileOutputStream.

You get a problem because you close the FileOutputStream in line 29, before your close the BufferedOutputStream in line 30. If you close the FileOutputStream first, then BufferedOutputStream can't flush the data anymore that it still might have in its buffer. So, the solution is to not close the FileOutputStream yourself; just let the BufferedOutputStream do that.

Make the finally-block look like this:

finally {
    bufferedInputStream.close();
    bufferedOutputStream.close();
}

Thank you very much....this foroum is really good and encouragimg me to read a lot because for any trouble I feel like there is some one who will help me like you people.

[Campbell Ritchie]

You should avoid the read() method of a Buffered reader; it has much better methods, eg readLine. Also, you should not use input streams and output streams for text files. Use readers and writers. The Java Tutorials has an example (under “buffered streams”) showing you how to create them. You can read like this

BufferedReader inBuff = ...
BufferedWriter outBuff = ...
String line;
while ((line = inBuff.readLine()) != null)
{
   outBuff.write(line);
   outBuff.newLine();
   System.out.println(line);
}
/* Now close both Streams */

If you keep going through the Java™ tutorials section, you come across Formatter and Scanner, which provide easier ways to read and write, but for text files only.

[Campbell Ritchie]

Maybe you should read this Java Tutorials section, too.