Java 8 File readAlllines map and reduce
<p>I have a text file as in /1/. The first column is product Volumn, and second column is product weight. My pupose it to calcuate total_Volumn/total_Weight. Earlier Java version has to read all lines, then parse, and for loop ...., anyway many lines. But this is calcuated by single thread. I would like to Java 8 feature, such us map, reduce, to make this calculation with few lines. Besides, the calculations is more efficient sine Java8 uses multi-threads  Any example?</p>

<p>/1/ textData.txt</p>

<pre><code>Volumn  Weight
1010.0  3458
34334   322
3434    343
3433    542
3134    146
3393    246
...
9787    3023
</code></pre>