Name: sdC67446 Date: 02/09/98


method java.util.zip.GZIPInputStream.read allows reading after calling method close().

Here is the JLS quote:
--------------------------------------------------
22.3.1 public abstract int read() throws IOException

The general contract of read is that it reads one byte from the input stream.
The byte is returned as an integer in the range 0 to 255 (0x00-0xff).
If no byte is available because the stream is at end of file,
the value -1 is returned.

This method blocks until input data is available,
end of file is detected, or an exception is thrown.

If the byte cannot be read for any reason other than end of file,
an IOException is thrown. In particular, an IOException is
thrown if the input stream has been closed (§22.3.6).

Here is the test demonstrating the bug:
-----------------Test.java------------------------
import java.util.zip.*;
import java.io.*;

public class Test {
  
  public static void main(String[] args) {
    
    try {
      InputStream bis = new ByteArrayInputStream(compressed);
      GZIPInputStream gis = new GZIPInputStream(bis);
      gis.close();
      int a = gis.read();
      System.out.println("Can read after close().");
    } catch ( IOException e ) {
      System.out.println("It's ok.");
    }
  }
  // compressed stub data
  static byte[] compressed = {
    31,-117,8,0,0,0,0,0,0,0,-85,-107,-79,74,85,97,117,48,
    -9,117,-47,114,15,-87,-27,-9,-54,-48,49,-108,17,19,20,
    118,-87,-84,78,-15,-10,-87,-112,51,115,16,85,81,54,11,
    114,44,11,98,116,17,102,-10,72,-10,80,-79,101,14,47,-50,
    16,117,-9,-83,16,13,-55,83,83,103,-30,-117,-42,-82,-105,
    -119,46,-16,20,-111,-85,-16,-48,54,79,-53,-76,116,
    -80,-78,77,-88,-85,50,113,-54,15,-74,-28,-44,101,-43,47,
    85,54,-74,1,0,85,69,28,117,100,0,0,0
  };
}
---------Output from the test---------------------
Can read after close().
--------------------------------------------------

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