javagit/src/main/java/edu/nyu/cs/javagit/utilities/CheckUtilities.java
public static void checkStringListArgument(List<String> str, String variableName) {
    if (null == str) {
      throw new NullPointerException(ExceptionMessageMap.getMessage("000002")
          + "  { variableName=[" + variableName + "] }");
    }
    if (str.size() == 0) {
      throw new IllegalArgumentException(ExceptionMessageMap.getMessage("000002")
          + "  { variableName=[" + variableName + "] }");
    }
    for (int i = 0; i < str.size(); i++) {
      checkStringArgument(str.get(i), variableName);
    }
  }
public static void checkStringListArgument(List<String> str, String variableName) {
    if (null == str) {
      throw new NullPointerException(ExceptionMessageMap.getMessage("000002")
          + "  { variableName=[" + variableName + "] }");
    }
    if (str.size() == 0) {
      throw new IllegalArgumentException(ExceptionMessageMap.getMessage("000002")
          + "  { variableName=[" + variableName + "] }");
    }
    for (int i = 0; i < str.size(); i++) {
      checkStringArgument(str.get(i), variableName);
    }
  }
Checks a <code>List&lt;String&gt;</code> argument to make sure it is not null, none of its
elements are null, and all its elements contain one or more characters. If the
<code>List&lt;String&gt;</code> or a contained <code>String</code> is null, a
<code>NullPointerException</code> is thrown. If the <code>List&lt;String&gt;</code> or a
contained <code>String</code> has length zero, an <code>IllegalArgumentException</code> is
thrown.

@param str
The <code>List&lt;String&gt;</code> to check.
@param variableName
The name of the variable being checked; for use in exception messages.