We have a legacy program that was ported from Java 1.3 to Java 1.5. This application involves applets which worked fine before. After porting however, the applet would not load. However there are no errors or exceptions. The app would just try to load it forever. We tried to run it with Java 1.6 and poof! No problems whatsoever. Isn't Java 6 backwards compatible? So how come it would run in that version and not in 1.5? ==== Java Console log for Java 1.5.0_19 basic: Registered modality listener basic: Registered modality listener basic: Registered modality listener liveconnect: Invoking JS method: document liveconnect: Invoking JS method: document liveconnect: Invoking JS method: document liveconnect: Invoking JS method: URL liveconnect: Invoking JS method: URL liveconnect: Invoking JS method: URL basic: Referencing classloader: sun.plugin.ClassLoaderInfo@bb7759, refcount=1 basic: Referencing classloader: sun.plugin.ClassLoaderInfo@bb7759, refcount=2 basic: Referencing classloader: sun.plugin.ClassLoaderInfo@bb7759, refcount=3 basic: Added progress listener: sun.plugin.util.GrayBoxPainter@b0bad7 basic: Loading applet ... basic: Initializing applet ... basic: Starting applet ... basic: Added progress listener: sun.plugin.util.GrayBoxPainter@ba9340 basic: Added progress listener: sun.plugin.util.GrayBoxPainter@1198891 basic: Loading applet ... basic: Initializing applet ... basic: Starting applet ... basic: Loading applet ... basic: Initializing applet ... basic: Starting applet ... basic: Referencing classloader: sun.plugin.ClassLoaderInfo@bb7759, refcount=4 basic: Releasing classloader: sun.plugin.ClassLoaderInfo@bb7759, refcount=3 basic: Referencing classloader: sun.plugin.ClassLoaderInfo@bb7759, refcount=4 basic: Releasing classloader: sun.plugin.ClassLoaderInfo@bb7759, refcount=3 basic: Referencing classloader: sun.plugin.ClassLoaderInfo@bb7759, refcount=4 basic: Releasing classloader: sun.plugin.ClassLoaderInfo@bb7759, refcount=3 network: Connecting <something>.jar with proxy=HTTP @ proxy/<ip address> basic: Loading <something>.jar from cache basic: No certificate info, this is unsigned JAR file. Left START init() Left END init() Right START init() Control start() Waiting for Left Panel to load... Right START start() network: Connecting socket://<ip address>:14444 with proxy=DIRECT Control start() Waiting for Left Panel to load... Control start() Waiting for Left Panel to load... Control start() Waiting for Left Panel to load... my HostName : <ip address> Thread-19 Check : Thread-19 Check : Monitor : run : start Thread-20 Monitor : Monitor: run() start Control start() Waiting for Left Panel to load... Control start() Waiting for Left Panel to load... Control start() Waiting for Left Panel to load... Control start() Waiting for Left Panel to load... Control start() Waiting for Left Panel to load... Control start() Waiting for Left Panel to load... the last message goes on forever... and now with the working version: ==== Java Console log for Java 1.6.0_15 basic: Added progress listener: sun.plugin.util.GrayBoxPainter$GrayBoxProgressListener@1b000e7 basic: Added progress listener: sun.plugin.util.GrayBoxPainter$GrayBoxProgressListener@12611a7 basic: Added progress listener: sun.plugin.util.GrayBoxPainter$GrayBoxProgressListener@1807ca8 network: CleanupThread used 6 us network: CleanupThread used 5 us network: CleanupThread used 6 us cache: Skip blacklist check as cached value is ok. network: Cache entry found [url: <something>.jar, version: null] network: Connecting <something>.jar with proxy=HTTP @ proxy/<ip address> network: ResponseCode for <something>.jar : 304 network: Encoding for <something>.jar : null network: Disconnect connection to <something>.jar Reading certificates from 11 <something>.jar | <something>.idx network: No certificate info for unsigned JAR file: <something>.jar basic: Applet loaded. basic: Applet loaded. basic: Applet resized and added to parent container basic: Applet resized and added to parent container basic: PERF: AppletExecutionRunnable - applet.init() BEGIN ; jvmLaunch dt 330275 us, pluginInit dt 27768955 us, TotalTime: 28099230 us Right START init() basic: PERF: AppletExecutionRunnable - applet.init() BEGIN ; jvmLaunch dt 330275 us, pluginInit dt 27770563 us, TotalTime: 28100838 us Left START init() basic: Applet loaded. basic: Applet resized and added to parent container basic: PERF: AppletExecutionRunnable - applet.init() BEGIN ; jvmLaunch dt 330275 us, pluginInit dt 27779332 us, TotalTime: 28109607 us Left END init() basic: Applet initialized basic: Removed progress listener: sun.plugin.util.GrayBoxPainter$GrayBoxProgressListener@12611a7 basic: Applet made visible And that's it. Still haven't figured out why it works with java6 and not java5. @valli: the object tag was used, not applet @thorbjorn: i tried that already... it just keeps saying loading applet... @aaron: how can i know what exception it is, if there really is one? and yes we have considered that its a java bug but i still havent found what that bug is. i have to submit a report tomorrow and i've scoured the net but came up with nothing as of yet... @all: thank you for your replies