Name: joT67522 Date: 01/09/98


(1) Run the enclosed test program under WindowsNT.
(2) Watch the threads get
java.util.zip.ZipException: invalid stored block lengths
until only one thread is running.

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import java.util.zip.Deflater;
import java.util.zip.DeflaterOutputStream;
import java.io.ByteArrayOutputStream;
import java.util.zip.Inflater;
import java.util.zip.InflaterInputStream;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.util.Date;

public class ZipEx {

public static void main(String[] args) throws IOException{
Object locker = new Object();
for (int i=0; i<10; i++) {
ZipThread t = new ZipThread(i, locker);
t.start();
}
}
}


class ZipThread extends Thread {
private int myNumber;
Object myLocker;

ZipThread(int n, Object locker) {
super("ZipThread "+n);
myNumber = n;
myLocker = locker;
}

public void run() {
int i = 0;
Date start = new Date();
System.out.println("Starting ["+myNumber+"] at " + start);
try {
byte[] data = new byte[256];

for (; i<2000000; i++) {
byte[] output;
ByteArrayOutputStream baos;
Deflater deflater;
DeflaterOutputStream deflaterOS;
baos = new ByteArrayOutputStream();
deflater = new Deflater(Deflater.DEFAULT_COMPRESSION, true);
deflaterOS = new DeflaterOutputStream(baos, deflater);

// Following synchronize needed to avoid:
// ZipException: invalid stored block lengths
//synchronized(myLocker) {
deflaterOS.write(data);
deflaterOS.close();
output = baos.toByteArray();
//}
ByteArrayInputStream bais = new ByteArrayInputStream(output);
Inflater inflater = new Inflater(true);
InflaterInputStream inflaterIS = new InflaterInputStream(bais, inflater);
byte[] input = new byte[data.length];
int off = 0;
for (;off<input.length;) {
int read = inflaterIS.read(input, off, input.length-off);
if (-1 == read) break;
off += read;
}
for (int j=0; j<input.length; j++) {
if (data[j] != input[j]) {
throw new Error("["+myNumber+"]data mismatch");
}
}
inflater.end();
// Following synchronize needed to avoid:
// ZipException: invalid stored block lengths
//synchronized(myLocker) {
System.gc();
System.runFinalization();
System.gc();
//}
}

} catch(OutOfMemoryError e) {
Date now = new Date();
System.out.println("\n["+myNumber+"]Out of memory at " + now + " i=" + i);
throw e;
} catch(IOException e) {
Date now = new Date();
System.out.println("\n["+myNumber+"]I/O Exception at " + now + " i=" + i);
e.printStackTrace();
}
Date end = new Date();
System.out.println("End ["+myNumber+"] at " + end + " i=" + i);
}
}
(Review ID: 22735)
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