java - PrintWriter not writing all Strings -

When I'm using PrintWriters, I have a lot of trouble problem I have 6 threads which each one has 2 different Running with print, including typing tofaiaaaa and tmp 0bbb, tmp1aaa, tmp1bbb etc. (... tmp5aa, tmp5bbb)

At the end of my run () method I get 2 array list, let's with the size of 1200 and 800.

 for  (string s: aaa_are) {// aaa_array size 1200.printaira.printlean (s); } (Strings: BBB_array) {// BBB_array size 800 this.printerBBB.println (s); }  

But when I check the size of 2 files, then I see only 1000 lines for the first TMP file and 700 for other (Example value, I do not have exact Value in mind)

Any ideas why I am losing the wire?