False Negative : Unsynchronized overrides of synchronized methods are missed

[Carlson-JLQ]

False Negative : Unsynchronized overrides of synchronized methods are missed

Affects errorprone Version:

2.48.0

Checker:

UnsynchronizedOverridesSynchronized

Description:

The official UnsynchronizedOverridesSynchronized checker warns when a subclass overrides a synchronized method with a method that is not synchronized. Both samples below match that description directly.

Code Sample demonstrating the issue:

// PosCase1
static class Parent {
    synchronized void method() {}
}

static class Child extends Parent {
    @Override
    void method() {
        // non-synchronized override
    }
}

// Sonar PosCase1
static class Parent {
    synchronized void synchronizedMethod() {
        System.out.println("Parent synchronized method");
    }
}

static class Child extends Parent {
    @Override
    void synchronizedMethod() {
        System.out.println("Child non-synchronized override");
    }
}

In both cases, the subclass removes the synchronized modifier from an overridden method, which weakens the thread-safety contract promised by the parent type.

Expected outcome:

Error Prone should report these overrides under UnsynchronizedOverridesSynchronized, but it doesn't. This is a false-negative.

[chrswk]

Both examples trigger UnsynchronizedOverridesSynchronized for me with 2.48.0.