For some reason, putting @Override on methods overriding interface methods causes JSP compilation to fail in weblogic. Everything is definitely running off of JDK 1.6.0_14, but this Java 5'ism still persists.
Oddly, JSP compilation occasionally fails with a stacktrace pointing at code not necessarily obviously used by the JSP itself.
What's going on here?
I've seen this a lot myself. In Java 6, it is (supposedly) permissible to use @Override on interface implementation methods. In Java 5, this is an error. However in my Java 6 code, sometimes @Override is accepted on interface implementation methods, and sometimes it is not.
To make things weirder, some IDEs (e.g. NetBeans) are fine with it, while IntelliJ IDEA is sometimes ok and sometimes not. I have found, however, that compiling the code in either IDE will ignore the alleged errors being reported by the IDE.
In other words, is the problem manifesting in your IDE? If so, compile the code directly (use the command-line if necessary) and see what happens. The IDE may be reporting spurious errors.
In my mind, @Override makes sense on methods that are overriding methods, not implementing methods.
So if you have an interface:
public interface MyInterface {
public void doSomething();
}
A class that implements that interface is below (MyClassA):
public MyClassA implements MyInterface {
public void doSomething() {
System.out.println("This is from MyClassA");
}
}
Then, the below class extends MyClassA and overrides doSomething, and so then I'd add the @Override annotation.
public MyClassB extends MyClassA implements MyInterface {
@Override
public void doSomething() {
System.out.println("This is from MyClassB");
}
}
I wouldn't do the below (whether or not it is permissable) in any case, since it breaks the idea about overriding something - you're implementing, not overriding the interface:
public MyClassA implements MyInterface {
@Override
public void doSomething() {
System.out.println("This is from MyClassA");
}
}
The @Override is supposed to only be retained in source so shouldn't come up in byte code. There might an angle you can play in ensuring those classes are complied separately from the JSPs and simply available in the classpath -- rather than the source path.
If that's already the case then it might be a different issue than what is immediately showing.
Used to be the JSP complier was a separate library shipped with the server and not tied to the vm the server is running in. WLS used to use Javelin. Seems like they switched that in 10 to use the Java Compiler API. So it should work fine as long as you have Sun vm Java 1.6. But if there's 'javelin' anything in your stacktrace, definitely check that angle.
Simply avoiding the annotation on implemented interface methods will resolve the issue. When doing team development with OSX users I run into this often due to Eclipse automatically adding @Override when implementing interfaces. The OSX guys get a compile error every time, even though it is technically valid. In my opinion, needing an annotation to a say I'm implementing an interface is lame since the interface method is nothing without an implementation :).
A possible workaround might be to precompile JSP using appc. This could at least allow to circumvent the issue.
Regarding the "real" question, my understanding is that you did upgrade domains, so maybe have a look at the following resources:
JSPCompilerBackwardsCompatible - Specifies whether to allow JSPs that do not comply with the JSP 2.0 specificationThis is a wild guess but maybe some backward compatibility flag is activated and WebLogic keeps using the "old" approach.
I agree with your instinct and the other answers that WLS is using Java 5 somehere. The items below seem like useful tidbits from Oracle/WebLogic resources. I don't have a WebLogic Server 10.3 installation to confirm these:
According to this, at least Weblogic Server 10.3 is required to use Java 6, but I can't see anything the confirms this as authoritative info:
Re: WebLogic 10.0 supports Java 6?
Posted: Apr 9, 2009 12:26 PM in response to: user8324142
Hi,
Weblogic 10 will not support JDK6.
Please upgrade to Weblogic 10.3 to work with JDK 6.
Determining Which JDK Version You Are Using
You can determine which version of the JDK you are using by issuing a command, as follows:
Open a command prompt window and go to the appropriate directory:
BEA_HOME\WL_HOME\server\bin (Windows)
BEA_HOME/WL_HOME/server/bin (UNIX)In both pathnames, BEA_HOME represents the directory in which you have installed your software and WL_HOME represents the wlserver_< version >.
Make sure that your environment is set up properly by entering the following command at the prompt: setWLSenv.cmd (Windows)
setWLSenv.sh (UNIX)Enter the following command at the prompt: java -version
Setting Java Parameters for Starting WebLogic Server
... Java parameters must be specified whenever you start WebLogic Server. ... Oracle recommends that you incorporate the command into a [startup] script ...
If you used the Configuration Wizard to create your domain, the WebLogic startup scripts are located in the domain-name directory where you specified your domain. By default, this directory is BEA_HOME\user_projects\domain\domain-name, where BEA_HOME is the directory that contains the product installation, and domain-name is the name of the domain directory defined by the selected configuration template. ...
Change the value of the variable JAVA_HOME to the location of your JDK. For example:
set JAVA_HOME=C:\bea\jdk150_03...