The attached patch removes the extra semicolon after the call to JType.genCDecl (which comes with its own semicolon already):
52 String genCDecl(String name)
53 return " " + mCName + " "+name+";\n";
The attached diff is against http://svn.apache.org/repos/asf/hadoop/zookeeper/trunk at revision 932666 specifically.
(Regenerated the files like this: rm -rf src/
/generated/ && ant compile_jute)
Testing done: I diff:ed the C and Java files that "ant compile_jute" generates in the ZK tree with and without this patch applied, and I confirmed that the only difference between the two is that with the patch applied the extra semicolon is not present any more. (Diff:ed like this: diff -ru src