FULL PRODUCT VERSION :
java version "1.9.0-ea"
Java(TM) SE Runtime Environment (build 1.9.0-ea-b82)
Java HotSpot(TM) 64-Bit Server VM (build 1.9.0-ea-b82, mixed mode)

also

java version "1.8.0_45"
Java(TM) SE Runtime Environment (build 1.8.0_45-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.45-b02, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Mac OS X 10.10.5 Yosemite
Darwin Kernel Version 14.5.0

EXTRA RELEVANT SYSTEM CONFIGURATION :
echo $JAVA_HOME
/Library/Java/JavaVirtualMachines/jdk1.9.0.jdk/Contents/Home

A DESCRIPTION OF THE PROBLEM :
When throwing an exception from Optional.orElseThrow(), the compiler fails to infer that a unchecked exception is thrown unless the Optional's element type T is specified.

Possibly related to JDK-8054569, but since it's still present in the latest 1.9 release (b82) I think this is separate.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1) Create a file called Test.java and paste in the supplied source code.
2) Run "javac Test.java"

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Clean compilation with no errors and output of Test.class to the same directory.
ACTUAL -
Compilation failed with an error, requiring the exception to be caught or declared on the method, despite it being a RuntimeException.


ERROR MESSAGES/STACK TRACES THAT OCCUR :
Test.java:12: error: unreported exception Throwable; must be caught or declared to be thrown
    Object value3 = opt3.orElseThrow(() -> new RuntimeException("Test Exception"));
                                    ^
Note: Test.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
1 error

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
// Test.java
import java.util.Optional;

public class Test {
  public static void main(String[] args) {
    Optional<Object> opt1 = Optional.of("foo");
    // fine
    Object value1 = opt1.orElseThrow(() -> new RuntimeException("Test Exception"));

    Optional<?> opt2 = opt1;
    // also fine
    Object value2 = opt2.orElseThrow(() -> new RuntimeException("Test Exception"));

    Optional opt3 = opt1;
    // compiler error
    Object value3 = opt3.orElseThrow(() -> new RuntimeException("Test Exception"));
  }
}

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

CUSTOMER SUBMITTED WORKAROUND :
Supply the element type for the Optional, either with a concrete type or a wildcard.