Difference between 2 pseudo codes

I am monitoring my java application through JProfiler when I came across a scenario where 2 almost segments of code resulted in different memory usage.

The code segments are

// Case 1    
for (String record : thisLine.split(","))

and

// Case 2    
String[] rowData = thisLine.split(",");
for (String record : rowData)

The memory usage in Case 1 exceeds that of Case 2 by 100 MB (approx). I do not understand what is causing such a high memory spike for Case 1.

Some additional informations :

1. thisLine is a String containing csv values
2. The for loop in both the cases runs 1500 times (since there are 1500 csv values)