Bug 107501 – REGRESSION (r131539): Java applet is not started after changing visibility from none to block

• Status: RESOLVED
• Resolution: FIXED
• Component: Java

[Andrew Herron]

Java Applets have a defined lifecycle (init, start, stop, destroy). Depending on the browser, when an applet is hidden may be told to stop; in that case when it is shown again it is supposed to be told to start again. This is documented in a Java tutorial:
http://docs.oracle.com/javase/tutorial/deployment/applet/lifeCycle.html

A recent change in Webkit has broken the management of this lifecycle.

Steps to Reproduce:
Extract the attached appletlifecycle.zip

1) Compile the applet using IntelliJ or by executing buildClasses.sh
2) Load test.html
3) Click on the "replicate" button

Expected Results:
Applet should hide, then half a second later re-appear with the "applet is running" message

Actual Results:
The div re-appears, but the applet inside it does not. If you open the Java console, the applet prints lifecycle messages - it will display init, start, stop and destroy but never start again.

Replicated in Webkit build r140374, as well as Chrome 24 on Linux, Windows and OS X (after restoring Java 6 as the active Java plugin).

Using Safari 6.0.2, FireFox or IE (on appropriate platforms) the applet re-appears with the running message and the start message appears in the Java console.

Note that some browsers don't stop the applet when hidden, and others (eg Safari/Webkit on OS X) require the test page to be run from a web server instead of locally.

Replicated with Java 1.6.0_38 and Java 1.7.0_11.

Regression:
We're not sure exactly when the regression occurred; we first observed this around the time that Chrome 24 was promoted to the stable channel.

[Andrew Herron]

Created attachment 183886 [details]
complete replication case

[Alexey Proskuryakov]

Regressed in <http://trac.webkit.org/changeset/131539>. Julien, Eric, can you look into this?

[Alexey Proskuryakov]

<rdar://problem/13087608>

[Julien Chaffraix]

Reverted the incriminated changeset in http://trac.webkit.org/changeset/142500. I haven't been able to reproduce this bug but it should be fixed.

[Andrew Herron]

Confirmed in build r142638. Thanks!