apache commons compress using 7zip

Question

i am trying to use the below code that i got from apache commons compress examples webpage to create a zip file using the sevenZ classes hoping it would be faster to compress than regular java zip. this is what my code looks like

public static void main(String[] args) {
    // TODO Auto-generated method stub
    try{
    BufferedInputStream instream = new BufferedInputStream(new FileInputStream("c:/temp/test.txt"));

    SevenZOutputFile sevenZOutput = new SevenZOutputFile(new File("c:/temp/7ztest.zip"));
    SevenZArchiveEntry entry = sevenZOutput.createArchiveEntry(new File("c:/temp/test.txt"),"blah.txt");
    sevenZOutput.putArchiveEntry(entry);
    byte[] buffer = new byte[1024];
    int len;
    while ((len = instream.read(buffer)) > 0) {sevenZOutput.write(buffer, 0, len);}

    sevenZOutput.closeArchiveEntry();
    sevenZOutput.close();
    instream.close();
    }catch(IOException ioe) {
        System.out.println(ioe.toString());

    }
}

i get this error which looks so unrelated

Exception in thread "main" java.lang.NoClassDefFoundError: org.tukaani.xz.FilterOptions at java.lang.J9VMInternals.verifyImpl(Native Method) at java.lang.J9VMInternals.verify(J9VMInternals.java:93)

i have the apache packages imported

import org.apache.commons.compress.archivers.sevenz.SevenZArchiveEntry; import org.apache.commons.compress.archivers.sevenz.SevenZOutputFile;

but not sure what the org.tukaani.xz.FilterOptions is, it doesnt look like it is part of the apace commons compress. Any thoughts?

Solution

As noted on the "Known Limitations" page at Apache Commons:

"the format requires the otherwise optional XZ for Java library."

This dependency is optional for the other formats, but you need it for 7zip.

<dependency>
  <groupId>org.tukaani</groupId>
  <artifactId>xz</artifactId>
  <version>1.5</version>
</dependency>

Comments

[Ivan Aranibar]

It is worth noting that when you will decompress de file it will throw an error because you compressed it into a 7z file but the extension is .zip

[Henrik Aasted Sørensen]

PSA: The current version of Apache Commons Compression (1.14) requires version 1.6 the xz.