Assertion¶

Check non null¶

It is recommended to use Objects.requireNonNull (with Objects being the one of Java 8):

Objects.requireNonNull(executionResult, "executionResult must not be null");

As for more advanced conditions, it is recommended to use Guava’s Preconditions.

In Wicket code, you can use Args.notNull, Args.notEmpty, Args.isTrue, Args.isFalse. Be careful to use the Args class from Wicket.