FULL PRODUCT VERSION :
java version "1.8.0_101"
Java(TM) SE Runtime Environment (build 1.8.0_101-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.101-b13, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Debian Linux - OS name: "linux", version: "3.13.0-40-generic", arch: "amd64", family: "unix"
Windows 7 (6.1.7601)

A DESCRIPTION OF THE PROBLEM :
When a derived interface changes the declared exception type from a fixed one to be a generic, compilation fails with an error.

The received error message:
/home/travis/build/phax/as2-lib/as2-lib/src/main/java/com/helger/as2lib/LambdaExceptionDeductionFuncTest.java:[31,51] get() in <anonymous com.helger.as2lib.LambdaExceptionDeductionFuncTest$> cannot implement get() in com.helger.as2lib.LambdaExceptionDeductionFuncTest.IThrowingGetter overridden method does not throw java.lang.Exception

The error can be reproduced with artificial class LambdaExceptionDeductionFuncTest provided in the source code section.

The problem disappears, if I spare the IBaseGetter like this:

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.StandardCharsets;
public class LambdaExceptionDeduction2FuncTest
{
  public static interface IThrowingGetter <EX extends Exception>
  {
    String get () throws EX;
  }

  public static void main (final String [] args) throws IOException
  {
    final InputStream aIS = new ByteArrayInputStream ("abc".getBytes (StandardCharsets.UTF_8));
    final IThrowingGetter <IOException> aGetter = () -> Character.toString ((char) aIS.read ());
    aGetter.get ();
  }
}


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Try to compile the class LambdaExceptionDeductionFuncTest from the Source Code.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The file should compile fine.
ACTUAL -
The current result is

/home/travis/build/phax/as2-lib/as2-lib/src/main/java/com/helger/as2lib/LambdaExceptionDeductionFuncTest.java:[31,51] get() in <anonymous com.helger.as2lib.LambdaExceptionDeductionFuncTest$> cannot implement get() in com.helger.as2lib.LambdaExceptionDeductionFuncTest.IThrowingGetter overridden method does not throw java.lang.Exception

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.StandardCharsets;

public class LambdaExceptionDeductionFuncTest
{
  public static interface IBaseGetter
  {
    String get () throws Exception;
  }

  public static interface IThrowingGetter <EX extends Exception> extends IBaseGetter
  {
    String get () throws EX;
  }

  public static void main (final String [] args) throws IOException
  {
    final InputStream aIS = new ByteArrayInputStream ("abc".getBytes (StandardCharsets.UTF_8));
    final IThrowingGetter <IOException> aGetter = () -> Character.toString ((char) aIS.read ());
    aGetter.get ();
  }
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
The workaround is to not use the base interface with the fixed defined getter class.