Name: jl125535 Date: 04/07/2004


FULL PRODUCT VERSION :
java version "1.5.0-beta2"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0-beta2-b45)
Java HotSpot(TM) Client VM (build 1.5.0-beta2-b45, mixed mode)

java version "1.4.2"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2-b28)
Java HotSpot(TM) Client VM (build 1.4.2-b28, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Linux 2.4.19-4GB

A DESCRIPTION OF THE PROBLEM :
The javadoc for java.utils.Properties says:
public Object setProperty(String key, String value)
Returns:
the previous value of the specified key in this property list, or null if it did not have one.

This is wrong. The code is:
public synchronized Object setProperty(String key, String value) {
        return put(key, value);
    }

It's obvious that this method doesn't take Properties.defaults into account.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run test case.
Expected output:
a =b
  Old value = b
Actual output:
a =b
  Old value = null


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Properties.setProperty() returns the value that is returned
for Properties.getProperty().
ACTUAL -
Properties.setProperty() does not return the value returned
by Properties.getProperty() when the value is only set
in the Properties.defaults put not in the properties themselves.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.util.*;

public class defprop {
    public static void main (String args[]) {
        Properties defprop = new Properties();
        defprop.setProperty("a","b");

        Properties prop = new Properties(defprop);
        System.out.println("a ="+prop.getProperty("a"));
        Object obj = prop.setProperty("a","c ");
        System.out.println("Old value = "+obj);
    }

}



---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Call getProperties before setProperties.
It's not a severe bug, but it's just really confusing.
It would perhaps even be enough to update the javadoc.
(Incident Review ID: 235458)
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###@###.### 2004-11-17 20:53:58 GMT