javax.annotation.Nonnull vs assert

java assert findbugs null-check
Gualtiero Testa picture Gualtiero Testa · Feb 11, 2013 · Viewed 16.9k times · Source

I'm using Findbugs and javax.annotation.Nonnull on method parameters.

On private methods I usually add an assert line to check for nullness like

private void myMethod(@Nonnull String str) {
    assert str != null
    ....

Latest Netbeans version (7.3rc2) is reporting that the assert check is not necessary (because of the Nonnull annotation). I'm not fully sure this is a Netbeans bug or not.

Can the assert line be removed because I specified the @Nonnull annotation ?

As far as I understand, the annotation is used only during static analysis while assert is, when enabled, active during execution so the twos are not alternative.

Answer

Christophe Roussy picture Christophe Roussy · Feb 14, 2013

The assert is evaluated at runtime, the annotation helps FindBugs catch problems during the analysis before runtime. As both checks are not really conflicting you could keep them both. I would find it annoying if my IDE told me to remove the assert.

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