[COLLECTIONS-299] ExtendedProperties.convertProperties loses non-String values

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Component/s: Core
• Assignee: Unassigned
• Reporter: Simon Kitching
• Created: 16/Jun/08 11:13
• Updated: 27/Nov/15 21:11
• Resolved: 28/Feb/13 19:37

Description

A Properties object normally has Strings as its values. But it does partially support non-String-typed values via the raw put and get methods inherited from Hashtable. And other Properties methods are aware that the value might not be a String; see documentation for methods propertyNames() and stringPropertyNames() for example.

ExtendedProperties.convertProperties does this:

for (Enumeration e = props.propertyNames(); e.hasMoreElements();) {
      String s = (String) e.nextElement();
      c.setProperty(s, props.getProperty(s));
}

Properties.propertyNames() returns the names of all keys in the set, regardless of the associated value's type. But Properties.getProperty(key) returns null if the value type is not a String. The call to c.setProperty invokes setPropertyInternal, which can pass this null value to Hashtable.put, which then throws a NullPointerException.

It's rather puzzling to have a valid (string-key, non-string-value) entry in the Properties object and get a NullPointerException.

Perhaps the call
props.getProperty(s)
can be changed to
props.get(s)

Alternately, at least documenting that this method does not support non-string values in the input Properties object would be useful.

Issue Links

• is superceded by: COLLECTIONS-351 Remove features now supported in the JDK