Class.arrayType() throws UnsupportedOperationException in jdk19+

[pshipton]

Issue #14598

Continuing to throw IllegalArgumentException as the cause for the UnsupportedOperationException is done for compatibility.

[pshipton]

jenkins compile amac jdknext

[pshipton]

jenkins compile amac jdknext

[pshipton]

jenkins compile amac jdknext

[pshipton]

jenkins compile amac jdknext

[pshipton]

Tested in grinders, which passed.
https://openj9-jenkins.osuosl.org/view/Test/job/Grinder/890 - java/lang/Class/ArrayType.java
https://openj9-jenkins.osuosl.org/view/Test/job/Grinder/892 - Jep334Tests jdk19
https://openj9-jenkins.osuosl.org/view/Test/job/Grinder/893 - Jep334Tests jdk18

[pshipton]

@tajila what do you think about this condition added to Class.arrayType(), to throw UnsupportedOperationException "if the number of dimensions of the resulting array type would exceed 255". This is a limitation that OpenJ9 doesn't have.
http://cr.openjdk.java.net/~iris/se/19/build/latest/api/java.base/java/lang/Class.html#arrayType()

The java/lang/Class/ArrayType.java test checks for this. I added a check so the test can pass, but we could also ignore it (exclude or modify the test) or challenge it.

[tajila]

AFAIK, no one relies on being able to create arrays with more than 255 dimensions. I see no harm in adhering to RI behaviour

[tajila]

perhaps something like this may be clearer

        Class<?> baseType = this;
    	for (int arrayCount = 0; baseType.isArray(); arrayCount++) {
    		if (arrayCount == 255) {
    			throw new IllegalArgumentException();
    		}
               baseType = baseType.getComponentType();

    	}

[pshipton]

For some reason I missed this comment.
Made this change and retested, which failed. It works when I changed the check to 254. Or I suppose I could start the count from 1 and check for 255 if you prefer.

[pshipton]

jenkins compile amac jdk19

[pshipton]

jenkins compile amac jdk19

[pshipton]

Rerun java/lang/Class/ArrayType.java with the update.
https://openj9-jenkins.osuosl.org/view/Test/job/Grinder/995 - passed

[pshipton]

@tajila when you get a chance to review.