Answer by ccpizza for string to string array conversion in java

Splitting an empty string with String.split() returns a single element array containing an empty string. In most cases you'd probably prefer to get an empty array, or a null if you passed in a null, which is exactly what you get with org.apache.commons.lang3.StringUtils.split(str).

import org.apache.commons.lang3.StringUtils;

StringUtils.split(null)       => null
StringUtils.split("")         => []
StringUtils.split("abc def")  => ["abc", "def"]
StringUtils.split("abc  def") => ["abc", "def"]
StringUtils.split(" abc ")    => ["abc"]

Another option is google guava Splitter.split() and Splitter.splitToList() which return an iterator and a list correspondingly. Unlike the apache version Splitter will throw an NPE on null:

import com.google.common.base.Splitter;

Splitter SPLITTER = Splitter.on(',').trimResults().omitEmptyStrings();

SPLITTER.split("a,b,   c , , ,, ")     =>  [a, b, c]
SPLITTER.split("")                     =>  []
SPLITTER.split("  ")                   =>  []
SPLITTER.split(null)                   =>  NullPointerException

If you want a list rather than an iterator then use Splitter.splitToList().