Thank you, got it.

https://docs.oracle.com/javase/7/docs/api/java/lang/Integer.html#valueOf(int)

Yes, first sentence is correct.
Second one I wonder because I read:


ublic static Integer valueOf(int i)

Returns an Integer instance representing the specified int value. If a new Integer instance is not required, this method should generally be used in preference to the constructor Integer(int), as this method is likely to yield significantly better space and time performance by caching frequently requested values. This method will always cache values in the range -128 to 127, inclusive, and may cache other values outside of this range.

Parameters:
    i - an int value.
Returns:
    an Integer instance representing i.
Since:
    1.5


meaning that numbers in range -127,128 are cached always,
i.e. never lead to object creation when invoked in that range.
The should sentence means that normally,
a new object is created only if an equivalent one is not yet cached.

See also

http://stackoverflow.com/questions/2974561/new-integer-vs-valueof

on boxing with reference to jls specification.
There explicitly equality of two integers means that they are the same.
Normally, valueOf is what is used for boxing/unboxing.

By the way, here we see, that we shall not talk about boxing
when we just mean conversion java-octave.

In ov-java.cc method
static bool
unbox (JNIEnv *jni_env, const octave_value& val, jobject_ref& jobj,
       jclass_ref& jcls)

There is a macro for conversion of primitive scalars.
This is in itself not so good.
Also, the JVM is forced to create objects.
If I have values 0 then each conversion creates a new one,
putting load on the gc.
It is bad style to do so.
Instead of new Integer(0), write Integer.valueOf(0)
and let the JVM decide whether to invoke a constructor or not.