Name: bsC130419 Date: 07/24/2001


java version "1.4.0-beta"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-beta-b65)
Java HotSpot(TM) Client VM (build 1.4.0-beta-b65, mixed mode)


My task is to subclass the class java.util.prefs.AbstractPreferences

1. Create a subclass which is not located in the java.util.prefs package of
java.util.prefs.AbstractPreferences and implement the
interface PreferencesFactory.

2. Set the property java.util.prefs.PreferencesFactory to the new factory.

3. Call Preferences p = Preferences.userRoot() or similar.

A listing which reproduces the bug is below. It contains three java files.

// start:BugTest.java
package test;
import java.util.prefs.*;
public class BugTest {
    static {
        System.setProperty("java.util.prefs.PreferencesFactory",
            "test.BugPreferencesFactory");
    }
    public static void main(String[] args) {
        Preferences p = Preferences.userRoot();
    }
}
// end:BugTest.java
// start: BugPreferencesFactory.java
package test;
import java.util.prefs.*;
public class BugPreferencesFactory implements PreferencesFactory {
    public Preferences userRoot() {
        return BugPreferences.root;
    }
    public Preferences systemRoot() {
        return BugPreferences.root;
    }
}
// end: BugPreferencesFactory.java
// start: BugPreferences.java
package test;
import java.util.prefs.*;
public class BugPreferences extends AbstractPreferences {
    static BugPreferences root = new BugPreferences(null, "");
    public BugPreferences(AbstractPreferences parent, String name) {
        super(parent,name);
    }
    protected void putSpi(String key, String value) {
    }
    protected String getSpi(String key) {
        return null;
    }
    protected void syncSpi() throws BackingStoreException {
    }
    protected void removeNodeSpi() throws BackingStoreException {
    }
    protected AbstractPreferences childSpi(String name) {
        return new BugPreferences(this,name);
    }
    protected void flushSpi() throws BackingStoreException {
    }
    protected void removeSpi(String key) {
    }
    protected String[] childrenNamesSpi() throws BackingStoreException {
        return new String[0];
    }
    protected String[] keysSpi() throws BackingStoreException {
        return new String[0];
    }
}
// end:BugPreferences.java

Running the follwing commandline:

java -cp . test.BugTest

leads to:

Exception in thread "main" java.lang.InternalError: Can't instantiate Preference
s factory java.lang.ClassNotFoundException: test/BugPreferencesFactory
        at java.util.prefs.Preferences.<clinit>(Preferences.java:191)
        at test.BugTest.main(BugTest.java:9)

As a hint the error is class loader related.
(Review ID: 128738)
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