Overriding a Java Abstract method - overrides nothing

[David]

Java Code:

1. public abstract class MyAbstractClass<T>{
2.    protected abstract T execute(Job job) throws Exception;
3. }

Scala Code:

I copy line 2 in the Java code and paste it into MyConcreteClass and Intellij automatically generates lines 3,4,5 and 6.

1. class MyConcreteClass extends MyAbstractClass[String]{
2.  
3.  @throws(classOf[Exception])

4.  override protected def execute(job: Job[_ <: Serializable]): String = {
5.    "test"
6.  }

7.
8. }

However, the compiler still complains that 

Method 'execute' overrides nothing.

Can someone please help me to figure out how to override the java method?

Thanks

David

[Clint Gilbert]

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Some more code would help. Does the Job class have type params?

On 11/21/2014 04:16 PM, David wrote:
> Java Code:
>
> | 1.publicabstractclassMyAbstractClass<T>{ 2. protectedabstractT
> execute(Jobjob)throwsException; 3.} |

>
>
> Scala Code:
>
> I copy line 2 in the Java code and paste it into MyConcreteClass
> and Intellij automatically generates lines 3,4,5 and 6.
>

> | 1.classMyConcreteClassextendsMyAbstractClass[String]{ 2. 3.

> @throws(classOf[Exception])
>
> 4. override protected def execute(job: Job[_ <: Serializable]):
> String = { 5. "test" 6. }
>
> 7. 8.} |
>
>
> However, the compiler still complains that Method 'execute'
> overrides nothing.
>
> Can someone please help me to figure out how to override the java
> method?
>
> Thanks
>
> David
>
>

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[David]

Sorry, here is the code for Job:

public class Job<T extends Serializable> implements BreachTask {
...
}

and

public interface BreachTask extends Serializable {
}

[Clint Gilbert]

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Aha, your Java code omits the type param completely. Try this:

override protected def execute(job: Job[_]): String

On 11/21/2014 04:52 PM, David wrote:
> |
>
> override protected def execute(job: Job[_ <: Serializable]): String
> = {
>
> |

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[David]

Thanks for the replies Clint, but it basically gives the same error:

(Note that com.amp.util.Job does not match

com.amp.util.Job[_].  To implement a raw type, use

com.amp.util.Job[_].

[Clint Gilbert]

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You should post a minimal self-contained example.

On 11/21/2014 05:26 PM, David wrote:
> Thanks for the replies Clint, but it basically gives the same
> error:
>
> (Note that com.amp.util.Job does not match com.amp.util.Job[_]. To
> implement a raw type, use com.amp.util.Job[_].
>
> On Friday, November 21, 2014 4:54:08 PM UTC-5, Clint Gilbert
> wrote:
>
> Aha, your Java code omits the type param completely. Try this:
>
> override protected def execute(job: Job[_]): String
>
>
>
> On 11/21/2014 04:52 PM, David wrote:
>> |
>
>> override protected def execute(job: Job[_ <: Serializable]):
>> String = {
>
>> |
>

> -- You received this message because you are subscribed to the
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> and stop receiving emails from it, send an email to
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> <mailto:scala-user+...@googlegroups.com>. For more options,
> visit https://groups.google.com/d/optout.

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[David]

Hi Clint, I've attached a very small jar file containing all the source files.

A compile gives the following error:

On Friday, November 21, 2014 5:31:28 PM UTC-5, Clint Gilbert wrote:

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You should post a minimal self-contained example.

On 11/21/2014 05:26 PM, David wrote:
> Thanks for the replies Clint, but it basically gives the same
> error:
>
> (Note that com.amp.util.Job does not match com.amp.util.Job[_].  To
> implement a raw type, use com.amp.util.Job[_].
>
> On Friday, November 21, 2014 4:54:08 PM UTC-5, Clint Gilbert
> wrote:
>
> Aha, your Java code omits the type param completely.  Try this:
>
> override protected def execute(job: Job[_]): String
>
>
>
> On 11/21/2014 04:52 PM, David wrote:
>> |
>
>> override protected def execute(job: Job[_ <: Serializable]):
>> String = {
>
>> |
>
> -- You received this message because you are subscribed to the
> Google Groups "scala-user" group. To unsubscribe from this group
> and stop receiving emails from it, send an email to
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> <mailto:scala-user+unsub...@googlegroups.com>. For more options,

[Jason Zaugg]

On Sat, Nov 22, 2014 at 8:53 AM, David <david...@gmail.com> wrote:

Hi Clint, I've attached a very small jar file containing all the source files.

A compile gives the following error:

Hi David,

You weere on the right track but were tripped up be a subtle problem: in the signature of MyScalaConcreteClass#execute you bounded the existential with scala.Serializable, rather than java.io.Serializable

I was able to compile this:

class MyScalaConcreteClass extends MyAbstractClass[String]{

  @throws(classOf[Exception])
  override protected def execute (job: Job[_ <: java.io.Serializable]):String = {
    "test"
  }

}

In Scala compilation units, imports of java.lang_, scala._, scala.Predef._ are implied.

​

-jason

[Som Snytt]

Who says the puzzlers are dead?

Long live the puzzlers.

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