Why does Eclipse complain about @Override on interface methods?

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I have an existing project that uses @Override on methods that override interface methods, rather than superclass methods. I cannot alter this in code, but I would like Eclpse to stop complaining about the annotation, as I can still build with Maven.

How would I go about disabling this error?

Note: Due to project requirements, I need to compile for Java 1.5.

10 Answers

Using the @Override annotation on methods that implement those declared by an interface is only valid from Java 6 onward. It's an error in Java 5.

Make sure that your IDE projects are setup to use a Java 6 JRE, and that the "source compatibility" is set to 1.6 or greater:

  1. Open the Window > Preferences dialog
  2. Browse to Java > Compiler.
  3. There, set the "Compiler compliance level" to 1.6.

Remember that Eclipse can override these global settings for a specific project, so check those too.


Update:

The error under Java 5 isn't just with Eclipse; using javac directly from the command line will give you the same error. It is not valid Java 5 source code.

However, you can specify the -target 1.5 option to JDK 6's javac, which will produce a Java 5 version class file from the Java 6 source code.

You could change the compiler settings to accept Java 6 syntax but generate Java 5 output (as I remember). And set the "Generated class files compatibility" a bit lower if needed by your runtime. Update: I checked Eclipse, but it complains if I set source compatibility to 1.6 and class compatibility to 1.5. If 1.6 is not allowed I usually manually comment out the offending @Override annotations in the source (which doesn't help your case).

Update2: If you do only manual build, you could write a small program which copies the original project into a new one, strips @Override annotations from the java sources and you just hit Clean project in Eclipse.

You can also try Retroweaver to create the Java5 version from Java6 classes.

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