[jdk16] RFR: 8259027: NullPointerException in makeMappedSegment due to NULL Unmapper when length of segment is 0
mcimadamore at openjdk.java.net
Tue Jan 5 13:02:03 UTC 2021
When the size of the memory map is zero, FileChannelImpl returns a `null` Unmapper - this creates issues to the mapped memory segment implementation.
To fix, I've created an empty mapped segment class which is initialized to sensible defaults, and whose implenentation of force/load etc. do nothing.
We already had a test for this condition - but the test was missing the `@Test` annotation, so it was not run! I've now beefed up the test a bit to make sure that mapped segment operations do not throw.
- Create subclass for empty mappings
- Return dummy mapping when mapping length is zero
Stats: 46 lines in 2 files changed: 40 ins; 2 del; 4 mod
Fetch: git fetch https://git.openjdk.java.net/jdk16 pull/83/head:pull/83
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