How to create a file that is highly compressable with Gzip (Deflate)?

Question

What characteristics does a file have, that is highly compressable using Gzip with the deflate algorithm.

I have a TSV File and I try to generate some more TSV files with the same compression rate. My original TSV file is about 700mb uncompressed and 40mb compressed.

I have tried to use longer strings which increased the compression rate (but not enough)

To write my files i use:

fileOutputStream = new FileOutputStream(outputFilePath);
GZIPOutputStream gzipOut = new GZIPOutputStream(fileOutputStream, 512000, false);
this.writer = new OutputStreamWriter(gzipOut, "UTF-8");
writer.write(line);  

Do you have any hints on how to recreate such a file?

Answer 1

Make a file with all zero bytes. As many as you like. If it's long enough, deflate will compress it approximately 1000:1.