FULL PRODUCT VERSION :
Java Plug-in 1.6.0_12
Using JRE version 1.6.0_12 Java HotSpot(TM) Client VM

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]

A DESCRIPTION OF THE PROBLEM :
After migrating to JRE 1.6.0 update 12 plugin, swing related code in our application fails with exception: null - Null PointerException.

This code was working till Jave plugin 1.6.0 update 11.
basic: exception: null.
java.lang.NullPointerException
at javax.swing.text.JTextComponent.getText(Unknown Source)
at UtilTextField.isValid(TestApplet.java:20)
at java.awt.Component.invalidateIfValid(Unknown Source)
at java.awt.Component.setLocale(Unknown Source)
at javax.swing.JComponent.<init>(Unknown Source)
at javax.swing.text.JTextComponent.<init>(Unknown Source)
at javax.swing.JTextField.<init>(Unknown Source)
at UtilTextField.<init>(TestApplet.java:17)


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Provided simplified source code which could reproduce the problem.
Just launch the html file which would inturn load the applet containing the problematic code. By using java plugin 1.6.0_12, the applet will fail to launch and in java console you should be able to see the exception.

Trying the same in Java plugin 1.6.0_11 and earlier works fine without any issues.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The same piece of code should work on new plugins as well.
While launching the sample html file provided with this report, an applet will be loaded with just a textfield present in it.
ACTUAL -
The html page shows "Error. click for details"
In the java console, exception stack trace is seen

ERROR MESSAGES/STACK TRACES THAT OCCUR :
Console log:
Java Plug-in 1.6.0_12
Using JRE version 1.6.0_12 Java HotSpot(TM) Client VM
User home directory = C:\Documents and Settings\vmarimuthu

----------------------------------------------------
c: clear console window
f: finalize objects on finalization queue
g: garbage collect
h: display this help message
l: dump classloader list
m: print memory usage
o: trigger logging
q: hide console
r: reload policy configuration
s: dump system and deployment properties
t: dump thread list
v: dump thread stack
x: clear classloader cache
0-5: set trace level to <n>
----------------------------------------------------

security: property package.access value sun.,com.sun.xml.internal.ws.,com.sun.xml.internal.bind.
security: property package.access new value sun.,com.sun.xml.internal.ws.,com.sun.xml.internal.bind.,com.sun.javaws
security: property package.access value sun.,com.sun.xml.internal.ws.,com.sun.xml.internal.bind.,com.sun.javaws
security: property package.access new value sun.,com.sun.xml.internal.ws.,com.sun.xml.internal.bind.,com.sun.javaws,com.sun.deploy
security: property package.access value sun.,com.sun.xml.internal.ws.,com.sun.xml.internal.bind.,com.sun.javaws,com.sun.deploy
security: property package.access new value sun.,com.sun.xml.internal.ws.,com.sun.xml.internal.bind.,com.sun.javaws,com.sun.deploy,com.sun.jnlp
security: property package.definition value null
security: property package.definition new value com.sun.javaws
security: property package.definition value com.sun.javaws
security: property package.definition new value com.sun.javaws,com.sun.deploy
security: property package.definition value com.sun.javaws,com.sun.deploy
security: property package.definition new value com.sun.javaws,com.sun.deploy,com.sun.jnlp
security: property package.access value sun.,com.sun.xml.internal.ws.,com.sun.xml.internal.bind.,com.sun.javaws,com.sun.deploy,com.sun.jnlp
security: property package.access new value sun.,com.sun.xml.internal.ws.,com.sun.xml.internal.bind.,com.sun.javaws,com.sun.deploy,com.sun.jnlp,org.mozilla.jss
security: property package.definition value com.sun.javaws,com.sun.deploy,com.sun.jnlp
security: property package.definition new value com.sun.javaws,com.sun.deploy,com.sun.jnlp,org.mozilla.jss
basic: Added progress listener: sun.plugin.util.GrayBoxPainter$GrayBoxProgressListener@df8f5e
basic: exception: null.
java.lang.NullPointerException
at javax.swing.text.JTextComponent.getText(Unknown Source)
at UtilTextField.isValid(TestApplet.java:20)
at java.awt.Component.invalidateIfValid(Unknown Source)
at java.awt.Component.setLocale(Unknown Source)
at javax.swing.JComponent.<init>(Unknown Source)
at javax.swing.text.JTextComponent.<init>(Unknown Source)
at javax.swing.JTextField.<init>(Unknown Source)
at UtilTextField.<init>(TestApplet.java:17)
at TestApplet.<init>(TestApplet.java:7)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at java.lang.Class.newInstance0(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at sun.plugin2.applet.Plugin2Manager.createApplet(Unknown Source)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Exception: java.lang.NullPointerException



REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
Source code:
------------------
import javax.swing.JApplet;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.text.PlainDocument;

public class TestApplet extends JApplet {
private JTextField fName = new UtilTextField();
public void init() {
JPanel content = new JPanel();
content.add(fName);
setContentPane(content);
}
}

class UtilTextField extends JTextField{
public UtilTextField(){
super(new PlainDocument(), "", 10);
}
public boolean isValid(){
String textStr = getText();
//...we are analysing textStr to decide the return value
return true;
}
}


HTML file:
-------------
<HTML>
 <HEAD>
  <TITLE> Test JText component </TITLE>
 </HEAD>
<applet code="TestApplet.class" archive="test.jar">
</HTML>

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

Release Regression From : 6u12
The above release value was the last known release where this
bug was not reproducible. Since then there has been a regression.