Collection
, Date
, Map
, Calendar
, etc.
Because such types are mutable, this construct may result in unexpected modifications of an object's state from outside the owning class. Although this construct may be useful for performance reasons, it is inherently prone to bugs.
The following mutable types are reported:
java.util.Date
java.util.Calendar
java.util.Collection
java.util.Map
com.google.common.collect.Multimap
com.google.common.collect.Table
The quick-fix adds a call to the field's .clone()
method.
Example:
class Log {
String[] messages;
...
String[] getMessages() {
return messages; // warning: Return of String[] field 'messages'
}
}
After the quick-fix is applied:
class Log {
String[] messages;
...
String[] getMessages() {
return messages.clone();
}
}
Use the Ignore assignments in and returns from private methods option to ignore assignments and returns in private
methods.