FULL PRODUCT VERSION :
java version "1.8.0"
Java(TM) SE Runtime Environment (build 1.8.0-b132)
Java HotSpot(TM) 64-Bit Server VM (build 25.0-b70, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.1.7601]

A DESCRIPTION OF THE PROBLEM :
When a postfix increment expression appears within the body of a lambda, it evaluates in the same way as a prefix increment expression.

Take for example


The output of this program is:

anonymous class returns: 0
lambda returns: 1

where you would expect it to return 0 in both cases.



STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Compile and run the code provided below. Inspect the output.




EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
We would expect the following output

anonymous class returns: 0
lambda returns: 0

since

t -> t++;

should be equivalent to

t -> {return t++;};


ACTUAL -
The following output

anonymous class returns: 0
lambda returns: 1

which shows that the value of the postfix decrement expression is the value of the variable after the new value is stored.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
public class Example {
public static void main(String[] args) throws Exception {
Supplier<Integer> s1 = new Supplier<Integer>() {
@Override
public Integer get(Integer t) {
return t++;
}
};
System.out.println("anonymous class returns: " + s1.get(0));

Supplier<Integer> s2 = t -> t++;
System.out.println("lambda returns: " + s2.get(0));
}
}

interface Supplier<T> {
T get(T t);
}
---------- END SOURCE ----------