With java 14 and 15 I now get:

 test libinterp/octave-value/ov-java.cc-tst
***** testif HAVE_JAVA; usejava ("jvm")
 n = javaObject ("java.lang.Float", 1.35);
 assert (n.compareTo (1.0), 1);
 assert (n.compareTo (1.35), 0);
 assert (n.compareTo (10), -1);
 assert (n.doubleValue (), 1.35, 1e7);
!!!!! test failed
[java] java.lang.ClassCastException: class java.lang.Double cannot be cast to class java.lang.Float (java.lang.Double and java.lang.Float are in module java.base of loader 'bootstrap')

Also:

octave:9> n = javaObject ("java.lang.Float", 1.35)
n =

<Java object: java.lang.Float>

octave:10> m = methods (n, '-full')
m =
{
  [1,1] = Float(java.lang.String) throws java.lang.NumberFormatException
  [2,1] = Float(double)
  [3,1] = Float(float)
  [4,1] = boolean equals(java.lang.Object)
  [5,1] = java.lang.String toString(float)
  [6,1] = java.lang.String toString()
  [7,1] = int hashCode()
  [8,1] = int hashCode(float)
  [9,1] = float min(float, float)
  [10,1] = float max(float, float)
  [11,1] = int floatToRawIntBits(float)
  [12,1] = int floatToIntBits(float)
  [13,1] = float intBitsToFloat(int)
  [14,1] = int compareTo(java.lang.Object)
  [15,1] = int compareTo(java.lang.Float)
  [16,1] = byte byteValue()
  [17,1] = short shortValue()
  [18,1] = int intValue()
  [19,1] = long longValue()
  [20,1] = float floatValue()
  [21,1] = double doubleValue()
  [22,1] = java.lang.Float valueOf(float)
  [23,1] = java.lang.Float valueOf(java.lang.String) throws java.lang.NumberFormatException
  [24,1] = java.lang.String toHexString(float)
  [25,1] = int compare(float, float)
  [26,1] = java.lang.Object resolveConstantDesc(java.lang.invoke.MethodHandles.Lookup) throws java.lang.ReflectiveOperationException
  [27,1] = java.lang.Float resolveConstantDesc(java.lang.invoke.MethodHandles.Lookup)
  [28,1] = java.util.Optional describeConstable()
  [29,1] = boolean isNaN(float)
  [30,1] = boolean isNaN()
  [31,1] = float parseFloat(java.lang.String) throws java.lang.NumberFormatException
  [32,1] = boolean isInfinite()
  [33,1] = boolean isInfinite(float)
  [34,1] = boolean isFinite(float)
  [35,1] = float sum(float, float)
  [36,1] = void wait(long, int) throws java.lang.InterruptedException
  [37,1] = void wait() throws java.lang.InterruptedException
  [38,1] = void wait(long) throws java.lang.InterruptedException
  [39,1] = java.lang.Class getClass()
  [40,1] = void notify()
  [41,1] = void notifyAll()
}

Should we change this test FAIL to XFAIL?

Dmitri.
--

In bug #53728, this same conversion error was reported for the Oracle Java 7 runtime, but with Short instead of Integer.

Is this with dev or with stable branch?

I can get fedora buildbots to build with java-9 as well (all I have to do is set JAVA_HOME) is this is of more interest.



Dmitri.

I still am getting this error with stable

octave:1> n = javaObject ("java.lang.Integer", 1.35)
n =

<Java object: java.lang.Integer>

octave:2> assert (n.compareTo (0), 1)
error: [java] java.lang.ClassCastException: java.base/java.lang.Double cannot be cast to java.base/java.lang.Integer
octave:2> __octave_config_info__ ("hg_id")
ans = 2b040946dc69

java-9-openjdk-9.0.4.11-4.fc27.x86_64

(so it also Xfails make check):

test libinterp/octave-value/ov-java.cc-tst
***** testif HAVE_JAVA; usejava ("jvm") <51804>
 n = javaObject ("java.lang.Integer", 1.35);
 assert (n.compareTo (0), 1);
 assert (n.compareTo (1), 0);
 assert (n.compareTo (2), -1);
!!!!! known bug: http://octave.org/testfailure/?51804
[java] java.lang.ClassCastException: java.base/java.lang.Double cannot be cast to java.base/java.lang.Integer
PASSES 15 out of 16 tests (1 known bug)
-verbaim-

Fedora buildbots still use java-8.

Dmitri.

It's not documented, I can only guess that the Comparable<T> interface also defines a compareTo(Object) method that internally tries to cast the object to type T.

I don't see any difference in the API, both Java 8 and 9 say that java.lang.Integer.compareTo takes java.lang.Integer as an argument. However, when Octave is inspecting the runtime for the method "compareTo", the result says that it takes an argument of type java.lang.Object, not Integer. Octave doesn't do any casting because it doesn't think it has to, but then when the method is called the exception is thrown.

Someone might want to look into the Java 9 runtime in more detail and find out why this is happening. I think it will take writing some Java code to iterate over the available methods in the Integer class and see what's different.

Sure, but I'd rather understand why the call isn't working the way it is.

In Java 9 I can construct an Integer with a double, and I can call compareTo with a double argument. I would like to know where Java 9 has changed something so that that is no longer possible. Particularly since Java 9 isn't actually released yet.

I saw this also when trying to build with Java 9. Do you know where the relevant change in the Java 9 API is?