Re: GWT 2.6.0 / Java 6: UnsupportedClassVersionError in DevMode

I just tried from the command-line (using Maven, and double-checking with both ps and jvisualvm) and can confirm that using a JDK 6, DevMode "just works".

That means it's a problem with how DevMode is launched from (your) Eclipse, possibly a bug in the Google Plugin for Eclipse if that's what you're using, but not a bug in GWT proper.

On Monday, February 10, 2014 2:29:29 PM UTC+1, Timo Hoepfner wrote:

Hi,

I recently updated to GWT 2.6.0. Since then I'm getting a UnsupportedClassVersionError in (regular) DevMode at runtime. A regular compile works fine. Explicitly setting the sourceLevel in der DevMode launcher arguments (-sourceLevel 6 or -sourceLevel 1.6) doesn't help. Changing the DevMode JRE to 7 works around the problem. 

I'm using Firefox ESR 24.3.0.

Here's the full error:

14:17:50.548 [ERROR] [ajaxadmin] Unable to load module entry point class com.google.gwt.useragent.client.UserAgentAsserter (see associated exception for details)

java.lang.RuntimeException: Deferred binding failed for 'com.google.gwt.useragent.client.UserAgent' (did you forget to inherit a required module?)

    at com.google.gwt.dev.shell.GWTBridgeImpl.create(GWTBridgeImpl.java:53)

    at com.google.gwt.core.shared.GWT.create(GWT.java:72)

    at com.google.gwt.core.client.GWT.create(GWT.java:86)

    at com.google.gwt.useragent.client.UserAgentAsserter.onModuleLoad(UserAgentAsserter.java:41)

    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

    at java.lang.reflect.Method.invoke(Method.java:597)

    at com.google.gwt.dev.shell.ModuleSpace.onLoad(ModuleSpace.java:411)

    at com.google.gwt.dev.shell.OophmSessionHandler.loadModule(OophmSessionHandler.java:200)

    at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:526)

    at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:364)

    at java.lang.Thread.run(Thread.java:695)

Caused by: java.lang.UnsupportedClassVersionError: com/google/gwt/useragent/client/UserAgentImplGecko1_8 : Unsupported major.minor version 51.0

    at java.lang.ClassLoader.defineClass1(Native Method)

    at java.lang.ClassLoader.defineClassCond(ClassLoader.java:637)

    at java.lang.ClassLoader.defineClass(ClassLoader.java:621)

    at java.lang.ClassLoader.defineClass(ClassLoader.java:471)

    at com.google.gwt.dev.shell.CompilingClassLoader.findClass(CompilingClassLoader.java:1121)

    at com.google.gwt.dev.shell.CompilingClassLoader.loadClass(CompilingClassLoader.java:1194)

    at java.lang.ClassLoader.loadClass(ClassLoader.java:247)

    at java.lang.Class.forName0(Native Method)

    at java.lang.Class.forName(Class.java:249)

    at com.google.gwt.dev.shell.ModuleSpace.loadClassFromSourceName(ModuleSpace.java:670)

    at com.google.gwt.dev.shell.ModuleSpace.rebindAndCreate(ModuleSpace.java:473)

    at com.google.gwt.dev.shell.GWTBridgeImpl.create(GWTBridgeImpl.java:49)

    at com.google.gwt.core.shared.GWT.create(GWT.java:72)

    at com.google.gwt.core.client.GWT.create(GWT.java:86)

    at com.google.gwt.useragent.client.UserAgentAsserter.onModuleLoad(UserAgentAsserter.java:41)

    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

    at java.lang.reflect.Method.invoke(Method.java:597)

    at com.google.gwt.dev.shell.ModuleSpace.onLoad(ModuleSpace.java:411)

    at com.google.gwt.dev.shell.OophmSessionHandler.loadModule(OophmSessionHandler.java:200)

    at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:526)

    at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:364)

    at java.lang.Thread.run(Thread.java:695)

Is there anything I can do about that?

Thanks for your help,

Timo

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