javagit/src/main/java/edu/nyu/cs/javagit/utilities/CheckUtilities.java
public static void checkNullArgument(Object obj, String variableName) {
    if (null == obj) {
      throw new NullPointerException(ExceptionMessageMap.getMessage("000003")
          + "  { variableName=[" + variableName + "] }");
    }
  }
public static void checkNullArgument(Object obj, String variableName) {
    if (null == obj) {
      throw new NullPointerException(ExceptionMessageMap.getMessage("000003")
          + "  { variableName=[" + variableName + "] }");
    }
  }
Performs a null check on the specified object. If the object is null, a
<code>NullPointerException</code> is thrown.

@param obj
The object to check.
@param variableName
The name of the variable being checked; for use in exception messages.